I'll be testing android when the next update is ready for testing. There will be some 4k videos that I'm not sure are going to play well with android OS, but if that doesn't work I'll probably look into just converting them to a lower resolution.
Basically, it's in the works but it won't be ready until the next update (hopefully soon). As for joiplay compatibility, I couldn't tell you as it's the first I've heard of it, sorry!