I agree with your reasoning. Everything you do on Google+ can be flagged, and you're at risk of losing your Gmail account by using Google+. Even a name change could put your whole account in jeopardy.
The worst part is there's very little you can do to give your side of the story. Their judgements are practically final unless you're sleeping with a Google employee who can have an internal chat to clear your name. But like I said, right now, you couldn't pay me to sign up to Google+. If it ever becomes mandatory, I'm moving my emails out.
I recommend setting up a local mail client (say Mail on the Mac, Thunderbird etc.). I just recently did this; the rationale being that I'd at least get to keep my e-mails and contacts.
So even if GMail conks out or they throw me out for whatever reason, the situation won't be that bad. I think Google's a great company that provides really important services, but I'd rather hedge my bets than rely on them completely.
That is incorrect. Name policy violations can result in your Google+ profile being suspended, but nothing at all will happen to your Gmail or other services.
Gmail accounts only get shut down if the user is a spammer, or under 13 (blame the law), or some other extreme circumstance like that. Having a non-"real" name will not cause that.
I know they say this, but I don't trust them that they'd ban you here but not there. I'd rather avoid it and know my Gmail account is 100% secure (or as close as it can be).