Hypothetical #1 is so far out there that I'm not ready to even respond to it.
I think hypothetical #2 is a distinct possibility, with a caveat. I think it's likely that Mueller finds that the president himself was not working directly with the Russians on the election, but that the campaign was so dysfunctional that they allowed hangers on who were involved to join, and also didn't do anything to stop or call attention to the Russian attack even though it was obvious it was going on.
I also think he'll find that Trump obstructed justice, not to cover his own involvement per se, but because a) his ego would not allow him to admit that Russia played a huge role in his election, b) that any investigation into Russian attacks on our election will likely reveal other improprieties that Trump Org were active participants in, your fraud and money laundering and such, and c) has naivety and sheer unqualification for the job made him think that he could actually do these things because he was president, and this is how he made things to away in his businesses.