Regarding GDrive problems:
OK the client has been released as well (5575/5576) please try using it once it is published on Google Play. The change on client is as follows: first it will try the old way (that failed for you guys). If it fails, it will give you a dialog with an error code (i NEED to know that error code, even if you proceed!) and an option to use the "Web method" to authenticate. This is an alternate method of authenticating we implemented as fallback but did never use - lets see if it helps.