I don’t think they can argue #1, because a lower court found that he had done insurrection, and my understanding is that they cannot overrule that finding. #2 won’t stand because it never required conviction historically.

I really don’t know how they’re going to justify it, but I’m sure they’ll find a way. Maybe it’s on your list.

Edit: I have consulted a legal expert, and they said that the supreme Court can overrule “facts” determined in other courts, but it is generally only for egregious things and is generally frowned upon.