Yes, all of that. Also, there are legal disclaimers and privacy notices and all kinds of thing beyond my IANAL ken that are wrapped up in agreeing to participate in Test Pilot. Nothing sneaky, just mainly we want to get lots of feedback while you're in, be totally up front about that, and clean up after ourselves when you leave.

Although, actually, the experiment installs are per-browser-profile and not necessarily sync'd if you haven't turned that on in your sync prefs. So if you wanted, you can try experiments in one release channel / profile, but not in another.

I don't use sync in general, so this particular instance of sync is not positive point to me.

And I don't see how the other things need an account.