A couple problems with your Hawkeye origin, besides the UIM-like need to explain his abilities. First, Hawkeye went to the Olympics for Archery, not gymnastics. It was never even said he had anything to do with gymnastics, and while I understand the reason of having him be in it in your origin, it goes against established continuity. I know you work around it and have Hawkeye in the Olympics for archery later on, but it seems kind of forced. Second, Hawkeye is the guy who helped start or form SHIELD, or was at the very least one of its earliest recruits based on the line he said to Fury in the first Ultimates volume about SHIELD being something or other with a drink tab. So that kind of makes it impossible for his father or grandfather to have been members. Oh and by the way, wasn't Callum the youngest kid, not the first? Or am I remembering wrong. Liked the Boomerang thing though, and the fact you kept him alive so he could later appear in USM without screwing up continuity. Needs some work, but not a bad idea. I'd just not rely so much on the explanation of Hawkeye's abilities.