1) Wisconsin is a comparative negligence state, he can certainly sue. Moreover he is innocent, until proven guilty, what makes you think the state has met that burden?Rittenhouse can't sue anybody. And he might end up paying out civil damages for wrongful death. You are assuming he will be found innocent. But what if he's not?
Because he pointed a gun at people which by law negates his claim of self defense.
Using the firearm doesn’t negate self defense. A person is allowed to defend themselves with a gun