Current music android app

I've looked and can't find any answers to a few ?'s I have. Hopefully someone here can help lol.

1) can I use the charging/ music option on multiple phones? If so what's the actual limit? 2) if I do use the charging option on multiple phones do I have to check into every phone to "claim" the points or can I do that from 1 phone? 3) is their a way to make it so that streaming music doesn't require a "check in" every 40 mins?

Thnx for any help provided