1. See below.
2. Unable to respond based on assumption of no conviction.
3. Impeaching a president and not getting a conviction is a waste of time.
EC. I would guess that Mueller is going down the money laundering and obstruction of justice rabbit holes. Collusion is a pretty broad term. I also think that if Mueller is doing his job that there are other avenues he's going down that aren't being reported...ie Saudi Arabia. To answer #1 properly it will all depend on how the investigation plays out in the coming months. If more charges are brought against the likes of Kushner or others in the inner circle then who knows.
I would like to ammend #3:
IF they were to bring legit articles of impeachement, and voted to do so, but did not achieve a conviction in the Senate maybe it isn't a waste of time for a 1st term president. Could an impeached president win a second term? Clinton was impeached during his second term so it's not an apples to apples scenario.