Basically if you play 7 days a week, you have 4 positions including DH and 5 guys, that's at least 5 games a week for everyone. Martin can still play 2 to 3 days a week, maybe you slot Keaschall in at 2B a couple days a week. I do think it is possible and remember when one of those guys is not starting, they are on the bench, I like my odds of pinch hitting with one of those players as the option. It is better to have too many options than having to put people in situations that are not optimal.
Yes the better would have been to trade Larnach, but I do not believe it is in the best interests of Jenkins or the team to keep him in St. Paul.
As for Caratini, he had a career month in St. Paul, he has basically reverted to his career norms which for a backup catcher and occasional fill in at 1B is perfectly acceptable. But they have basically made him a platoon option and late inning defensive replacement, moving three or four players around, let's minimize if we can.