Quick update:
Okay got everything figured out, just a few very small things that were causing the problems in the end.
1) Lemmy, in ci_init.py, around line 259 there's this:
userbg = userbg.replace("file://", "")

Just go in after that an add another condition to fix the spaces in your filename:
userbg = userbg.replace("%20", " ")

I've tested it on one of my tablets and confirmed that this resolves the background problem.

2) I finally managed to reproduce the osso.deviceState problem, and have fixed it in the development files here so the next version of the app will not generate any errors related to this. It works in the current version after the update I made last night, but it'll be properly properly fixed as of the next release.

3) The one thing I can't duplicate is the "setting alarm" thing hanging there for a few minutes the first time I run the app, but I'll keep trying at that.