I would keep all three and use McSorley as a Swiss Army knife.
I don’t think there are a lot of guys making great cases for the 53rd man on the roster where you might miss out if you keep 3 QBs instead of 2 and a different guy.
I think they keep McSorely. I realize it's not the road they like to go down(3 QB's) but if they throw him on the practice squad, he's as sure as gone because someone's going to take a flyer on him at some point. They'll just have to sacrifice someone somewhere else on the roster.