There seems to be two different answers to this question and I don't know which one is correct. One is to simply delete the beta profile from settings. The second is to do that along with resetting your phone to factory settings and applying a backup from before you installed the beta. The first option is what two people from Apple support told me, so I'm going with that for now. If I see that my iPad gets an update (which never had the beta) and my phone doesn't, or my phone gets another beta update, then I will reset.
There won't be public beta updates for incremental updates to iOS 10. When 10.0.2, 10.1, or whatever comes out, it'll show up on your phone and you updater. Or not. Your choice.
If you're on the beta, you'll get notifications for betas for the incremental builds before they become official.
The beta GM and the Official release are the same, but they may have different results. My situation:
I wanted out of the beta program for the Watch and phone so I could get the Official Release along with everybody else, not the GM a week earlier. Yes I know they're the same. I tossed the both the phone and Watch beta profiles, restarted both devices, and stopped downloading the betas for both devices.
When the 13th rolled around, I hadn't updated my phone to GM, so I was able to get the Official release, along with the unwashed masses. lol However I apparently updated to the wOS GM instead of stopping at the last beta, I never got the Official Release for the Watch as it was 'up to date'.
So I'm waiting to see what I get next- a notification about a new beta build or the Official release of the next update.