Samsung can't speculate any updates then, there will be an official announcement and you will see a banner on the Samsung members app when ready
AT&T does not do public betas. If you have an unlocked phone however (U1) you may still participate in the beta regardless if your carrier is AT&t or Verizon
Thank you! By the way, Samsung should treat Wi-Fi variants of the Galaxy Tab series as U1 (open market) variants, to make beta programs more widely available. If this beta program does not come to tablets, then it will cause problems when it comes to testing for larger screens.