Well well, so jessie is recent enough to have systemd...
The kernel got as far as trying to launch the first userland process (init, PID 1).
And systemd init then launches a whole bunch of daemons that are listed in your pic 1531.
In your first pic there's that __do_page_fault call in the trace (and handle_mm_fault as well).
But it not clear to me where exactly this was originated. If it's caused by systemd-udevd, adding the debug switch -D might help.
systemd-udevd is probably launched from lib/debian-installer/start-udev (that script resides inside of the initrd.gz image, might not be that simple to edit).
Do note that there are some distros without systemd such as Devuan and Void Linux for example.
But for UniPCemu Linux testing, alpine or Slackware are better alternatives than those two, because of the lack of an FPU.
The latest alpine versions (after 3.12) do require FPU by default though.
With alpine-extended-3.4.6-x86.iso the boot actually gets pretty far, but eventually drops into an emergency shell.
The other alpine versions barf various errors (something like "Fatal exception in interrupt").