Yeah, you're absolutely right. No issues building on Jessie stable.

Thanks to everyone involved in making it so easy for a n00b to exercise init freedom, I really do appreciate it and yes I fully understand I have no inkling of all the work involved! Thank you and congratulations!

antiX 15 Killah - no problems

Great!
Initial result was an offer from apt-get dist-upgrade to remove init and 200MB or so:
The following packages will be REMOVED:
antix-cc-full-antix baloo-utils baloo4 bluetooth bluez brasero ceni cmake colord conkeror connectshares-antix console-setup console-setup-linux cups
cups-core-drivers cups-daemon firefox-esr gnome-ppp gufw gvfs gvfs-daemons iceweasel init initramfs-tools initramfs-tools-core initscripts k3b katepart
kde-config-tablet kde-runtime kdelibs-bin kdelibs5-dev kdelibs5-plugins kdoctools libakonadi-kde4 libakonadi-kmime4 libbaloofiles4 libk3b6 libk3b6-extracodecs
libkabc4 libkatepartinterfaces4 libkcddb4 libkcompactdisc4 libkde3support4 libkdewebkit5 libkemoticons4 libkfile4 libkhtml5 libkimproxy4 libkio5 libkmediaplayer4
libknewstuff2-4 libknewstuff3-4 libknotifyconfig4 libkparts4 libkpimutils4 libkprintutils4 libkrossui4 libktexteditor4 libkunitconversion4 libkutils4
libkxmlrpcclient4 libpam-systemd libplasma3 libsane libsolid4 midisport-firmware nfs-common openssh-server plasma-scriptengine-javascript policykit-1 ppp
printer-driver-gutenprint printer-driver-hpcups procps rpcbind simple-scan systemd sysv-rc sysv-rc-conf sysvinit sysvinit-core sysvinit-utils udev udisks udisks2
umts-panel2 unetbootin upower wvdial xserver-xorg-input-all xserver-xorg-input-vmmouse
The following NEW packages will be installed:
makedev wine-mono4.6.2
The following packages have been kept back:
libarchive13
The following packages will be upgraded:
antix-libs apt-antix bsdutils chromium-inspector desktop-defaults-core-antix install-meta-antix libav-tools libblkid1 libfdisk1 libmount1 libsmartcols1 libudev1
libuuid1 live-usb-cli-antix mount opera-developer util-linux uuid-runtime vivaldi-stable wine-staging wine-staging-i386
WARNING: The following essential packages will be removed.
This should NOT be done unless you know exactly what you are doing!
init sysvinit-core (due to init) sysvinit-utils
21 upgraded, 2 newly installed, 92 to remove and 1 not upgraded.
Need to get 168 MB of archives.
After this operation, 215 MB disk space will be freed.

if only I wrote 'Do as I say!' I could nohup process 0 with...legume water or something. Stupid init process thinks its all that.

Later update went along and I got an improved:

apt-get dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
gir1.2-polkit-1.0 golang-go.crypto-dev gstreamer-tools gstreamer0.10-plugins-ugly hplip-data libaacplus2 libappindicator3-1 libapt-inst1.7 libapt-pkg4.16
libasn1-8-heimdal libavcodec56 libavdevice55 libavdevice56 libavfilter5 libavformat56 libavresample2 libavutil54 libbind9-90 libboost-regex1.58.0
libboost-signals1.58.0 libchromaprint0 libcloog-isl4 libcolamd2.8.0 libcommons-lang-java libcr0 libdbusmenu-gtk3-4 libdns100 libept1.4.16 libftdi1 libgcj15
libgettextpo0 libgif4 libglew1.10 libgnutls-openssl27 libgphoto2-port10 libgroupsock7 libgssapi3-heimdal libhcrypto4-heimdal libheimbase1-heimdal
libheimntlm0-heimdal libhx509-5-heimdal libilmbase6v5 libindicator3-7 libisc95 libisccc90 libisccfg90 libisl13 libjson0 libkrb5-26-heimdal libkvazaar0
libkvazaar2 liblinear1 liblivemedia49 liblivemedia50 liblwres90 libntdb1 libopenexr6v5 libopenh264-0 liborcus-0.10-0v5 libpgm-5.1-0 libplatform1.0
libpolkit-backend-1-0 libpoppler46 libpostproc53 libprocps4 libqpdf13v5 libquvi-scripts libquvi7 libroar-compat2 libroar2 libroken18-heimdal libsane-hpaio
libslp1 libsodium13 libsrtp0 libsuitesparseconfig4.4.5 libswresample1 libswscale3 libsysfs2 libtrio2 libupower-glib3 libval14 libvo-aacenc0 libvpx2 libvte-2.90-9
libvte-2.90-common libwind0-heimdal libwine-gecko-2.21 libx264-142 libx265-59 libx265-68 libzip2 libzmq3 python-cups python-dbus-dev python-gst0.10
python-libxml2 python-ntdb python3-pexpect python3-pil python3-ptyprocess python3-reportlab python3-reportlab-accel ruby-slop ruby2.2-dev wine-gecko2.44
wine-mono4.5.6 wine-mono4.6.2 wine-staging wine-staging-i386
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
colord gufw libpam-systemd policykit-1 systemd
The following NEW packages will be installed:
wine-mono4.6.2
The following packages have been kept back:
libarchive13
The following packages will be upgraded:
antix-goodies antix-libs apt-antix bsdutils chromium-inspector desktop-defaults-core-antix install-meta-antix libav-tools libblkid1 libfdisk1 libmount1
libsmartcols1 libudev1 libuuid1 live-usb-cli-antix mount opera-developer udev util-linux uuid-runtime vivaldi-stable wine-staging wine-staging-i386
23 upgraded, 1 newly installed, 5 to remove and 1 not upgraded.
Need to get 169 MB of archives.
After this operation, 21.8 MB of additional disk space will be used.

deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"http://antix.daveserver.info/testing"
linktext was:"http://antix.daveserver.info/testing"
====================================
testing main nosystemd dev
deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"http://ftp.gr.debian.org/debian/"
linktext was:"http://ftp.gr.debian.org/debian/"
====================================
jessie main contrib non-free
deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"http://security.debian.org/"
linktext was:"http://security.debian.org/"
====================================
jessie/updates main contrib non-free
deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"http://main.mepis-deb.org/mx/testrepo/"
linktext was:"http://main.mepis-deb.org/mx/testrepo/"
====================================
mx15 test
deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"https://deb.opera.com/opera-developer/"
linktext was:"https://deb.opera.com/opera-developer/"
====================================
stable non-free
deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"ftp://ftp.spline.de/pub/siduction/base/"
linktext was:"ftp://ftp.spline.de/pub/siduction/base/"
====================================
unstable non-free contrib main
deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"ftp://ftp.spline.de/pub/siduction/fixes/"
linktext was:"ftp://ftp.spline.de/pub/siduction/fixes/"
====================================
unstable main contrib non-free
deb-src
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"ftp://ftp.spline.de/pub/siduction/base/"
linktext was:"ftp://ftp.spline.de/pub/siduction/base/"
====================================
unstable main contrib non-free
deb-src
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"ftp://ftp.spline.de/pub/siduction/fixes/"
linktext was:"ftp://ftp.spline.de/pub/siduction/fixes/"
====================================
unstable main contrib non-free
deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"http://repo.vivaldi.com/archive/deb/"
linktext was:"http://repo.vivaldi.com/archive/deb/"
====================================
stable main
deb
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"http://repo.vivaldi.com/stable/deb/"
linktext was:"http://repo.vivaldi.com/stable/deb/"
====================================
stable main

on something like
System: Host: PrintroomDELLBlau Kernel: 4.3.0-antix.2-486-smp i686 (32 bit gcc: 5.2.1) Desktop: Fluxbox 1.3.5
Distro: antiX-15-V_386-full Killah P 30 June 2015
Machine: System: Dell product: Dimension XPS serial: 79XB361
Mobo: Dell model: 0K3464 serial: ..CN4811148L00WA. Bios: Dell v: A03 date: 10/11/2004
CPU: Single core Intel Pentium 4 (-HT-) cache: 1024 KB flags: (pae sse sse2 sse3) bmips: 6783
clock speeds: max: 3391 MHz 1: 3391 MHz 2: 3391 MHz
Graphics: Card: NVIDIA G98 [GeForce 8400 GS Rev. 2] bus-ID: 01:00.0
Display Server: X.org 1.18.3 drivers: nouveau (unloaded: fbdev,vesa)
tty size: 165x53 Advanced Data: N/A for root
Network: Card-1: Realtek RTL-8100/8101L/8139 PCI Fast Ethernet Adapter
driver: 8139too v: 0.9.28 port: cc00 bus-ID: 04:02.0
IF: eth0 state: down mac: 00:0e:2e:2a:b1:27
Card-2: D-Link System DWA-140 RangeBooster N Adapter(rev.B2) [Ralink RT3072] usb-ID: 002-002
IF: N/A state: N/A speed: N/A duplex: N/A mac: N/A
Drives: HDD Total Size: 296.0GB (66.6% used) ID-1: /dev/sda model: SAMSUNG_SP2004C size: 200.0GB temp: 43C
ID-2: /dev/sdb model: Maxtor_6Y080M0 size: 80.0GB temp: 46C
ID-3: /dev/sdc model: Name n/a size: 15.9GB temp: 0C
Partition: ID-1: / size: 62G used: 59G (100%) fs: ext4 dev: /dev/sda1
ID-2: swap-1 size: 2.17GB used: 0.36GB (17%) fs: swap dev: /dev/sda2
ID-3: swap-2 size: 3.76GB used: 0.00GB (0%) fs: swap dev: /dev/sdb3
Info: Processes: 203 Uptime: 16 days Memory: 1439.5/2015.7MB Init: SysVinit runlevel: 5 Gcc sys: 5.3.1
Client: Shell (bash 4.3.421) inxi: 2.2.31

Is that then sensible to try?
Edit: It was! It didn't make a kittenish drive whole again, and I had to reselect a terminal font in order to not be typing and reading 50% gibberish, but it worked without bricking anything that hadn't itself bricked, (like Firefox self-updating on <120MB.) Oh well, only 5 other firefoxes to choose among. Thanks! 70,000x better than Win10 migration on any hardware (and they probably ship a Red Wedding Surface.)

Edit involving things that aren't reproducible in themselves: k3b quits early because
Maximum number of clients reached
(k3b:10743): Gtk-WARNING **: cannot open display: :0.0
unnamed app(10742): Communication problem with"k3b" , it probably crashed.
Error message was:"org.freedesktop.DBus.Error.NoReply" :""Message recipient disconnected from message bus without replying""
(Ran fine following system lockup and reboot.)
and flobopuyo because
Maximum number of clients reachedSDL initialisation error: Couldn't open X11 display
...fine, asunder even:
(same story. Even P4 can become carbon-conscious over time.)
Maximum number of clients reached
(asunder:16298): Gtk-WARNING **: cannot open display: :0.0
...a look at dmesg reveals noveau complaining in this vein:
[44061.114313] nouveau 0000:01:00.0: fifo: CACHE_ERROR - ch 5 [opera-developer[3643]] subc 0 mthd 0060 data beef0201
[217982.462409] nouveau 0000:01:00.0: fifo: DMA_PUSHER - ch 2 [Xorg[2835]] get 002002604c put 0020026f08 ib_get 00000234 ib_put 00000239 state 8000e6a4 (err: INVALID_CMD) push 00700031
[218497.298353] nouveau 0000:01:00.0: fifo: DMA_PUSHER - ch 2 [Xorg[2835]] get 0020025314 put 0020026d74 ib_get 000002a4 ib_put 000002a7 state 8000f5dc (err: INVALID_CMD) push 00500031
[218497.310324] nouveau 0000:01:00.0: gr: DATA_ERROR 0000000d [BEGIN_END_ACTIVE]
[218497.310338] nouveau 0000:01:00.0: gr: 00100000 [] ch 2 [001fb21000 Xorg[2835]] subc 7 class 8297 mthd 1360 data 00000001
[218497.310355] nouveau 0000:01:00.0: gr: DATA_ERROR 0000000d [BEGIN_END_ACTIVE]
[218497.310362] nouveau 0000:01:00.0: gr: 00100000 [] ch 2 [001fb21000 Xorg[2835]] subc 7 class 8297 mthd 1340 data 00008006
[218497.310376] nouveau 0000:01:00.0: gr: DATA_ERROR 0000000d [BEGIN_END_ACTIVE]

brasero initialized normally. Opera is humming along here...

Change your sources.list back to the default and try a dist-upgrade

You have a mixture of stable, tesing and sid. No wonder there are dependency issues