You have it right. Wyatt was to young to go. His brothers all served. I work with Virgil's great, great, great, great grandson. He promised to check with his father to see what he might know about VIrgils service but I have not heard back. They all were for the most part, railroad guards as best as I know.
As far as Wild Bill is concerned, he came from the same area in western Illiniois as the Earps. I don't know if they knew each other then or not. It is possible he killed that many. Was pretty good with that .36 of his. Killed a man in Springfield, Mo. with it for sure.
Lot of what we hear about most of those guys come out of dime novels I think.