Trump has brought all this on by himself:
1) If he had hired a competent campaign manager, the Donald Jr. meeting would have never happened. Instead of notifying the FBI, Manafort actually attended the meeting.
2) There was absolutely no reason to fire Comey. Trump compounded it by admitting it was because of the Russia investigation.
3) A good attorney would have advised against the NDAs. It's questionable whether they're even enforcable and there's nothing to prevent the other party from disclosing their existence. Anyone who wasn't swayed by the Acess Hollywood tape wouldn't have cared about Trump having an affair or a tryst with a porn star.
4) As soon as the campaign started, any contact with Russia needed to end. That's a no-brainer.
Without any of the above there would be no Mueller investigation.
I have no idea what will be in the Mueller report, but Trump is a stupid man that makes bad decisions and doesn't follow the rules, so it's very possible there could be enough in the report to bring him down.