your google music is automatic once you log in to it
i have formatted multiple times (galaxy nexus roms)
and i sign in to music every time (after 10 times you have to deauthorize some devices)
and each time it resyncs everything.
most apps would work for tablets, however im not 100% certain, you might find some that arent compatible, and wallpapers may be the same, but then again im not sure.
i know all your google stuff will re-sync automatically