Pretty much an academic point, really. Consider if there was enough evidence of a state crime, like murder, and indictment by a state DA. All sorts of possibilities.
Generally figured that for federal offenses, there would not be an indictment - but if the allegations were serious enough, the order of procedure would be irrelevant for practical purposes.
If Mueller finds something he thinks is criminal, he will not indict, and it is contrary to DOJ rules that he even apprise the public of such a finding.
Well, if POTUS felt persecuted he could fire the prosecutor... Sure, impeachment would likely follow e.g.: Richard Nixon and then etc... just saying. Impeachment is a political procedure, not legal. POTUS could be impeached for his hair e.g.: Maxine Waters style or color.
This is why MSM constantly tries to separate Trump from his base. A while back I saw some MSM news moll attacking an evangelical in intvu for continuing to support Trump in light of Stormy Daniels. Ridiculous from those who defended Bill Clintooon, Ted Kennedy, et al.
Trumps 'base' seems to realize this. Well, we will see.