Needed to fiddle around with some settings, but I didn't need to alter any code at all which was refreshingly unexpected. Not going to post a preview at this time as I used the Koharu sample model to make sure things would work before getting into content production in case I'd have to change my approach, but it looks like I'll be able to do things exactly as imagined.

Solved my SDK/JDK issues and managed to get simple AR working in a simple Android apk!