This is the elephant in the room that can't be touched, here or anywhere else.
While each shooting might be a legitimate act of self-defense, if Rittenhouse left the group at the boarded-up business on his own, then the whole portrayal of him as a protector goes right out the window; he set himself up for trouble, and found it in spades.
IMO all three were self defense. The problem he may have, and I have to think the basis of the murder charges, an illegal act barring the self defense act. Like accompanying your friend to "peacefully" rob a bodega, your friend shoots the bodega owner, you can be charged with murder. Of course that's not self defense, but it's the concept they'll use I suspect. I also think the chase changes things. If he shot a looter protecting the building he was at, perhaps. But he was clearly being pursued and fired in self defense.
I chuckle a bit at the comments of we/he can do this, can do that, it doesn't matter. The 2nd amendment and all, we can do anything at any age. One can, until something happens. I'm glad Kyle has good pro bono council, but an incident like this is a life ender, at least financially, for the non multi millionaires among us. And there's always the possibility that a jury will find by his presence illegally in possession of a firearm he provoked the incident, in which case his life is over. Probably not in Kenosha with competent council. In Portland, Seattle or San Francisco, who knows. Personally I think being there armed at his age was a mistake, whether with his father of not.
https://www.scribd.com/document/474027394/Pierce-Bainbridge-Statement-on-Kyle-Rittenhouse-8-28-20