Without the log info it is almost impossible to help you.
I'm sure there are other ways to save this log for out of virtual os environment use. For example try to mount a flash usb dedicated to vbox and save to it (unmount from native), I have never used vbox on linux but I do this on Windows.
You can also try opera (from classic nemesis) as discussed in a previous topic and send from there.
If you use a save.dat file for your experiments you can backup it easily and if you get a stable system switch to a native partition.
If you save a good working state on a save.dat, you could save it and switch to it for clean xzm creations. There could be issues because pman script does not create xzm on re-installations, Instead classic pacman is used.
Try to use a bare nemesis without changes, there could be a misbehavior in your system (I guess virtual disk but native partition save?).
You could save keyring packages in xzm. Your changes partitions seems broken but I will never know. Maybe you have to start from scratch.
"missing libraries" should not happen often on official packages, something else had happened. Maybe you mean conflicting files.
Do not forget: Try to use pamac-manager