I'm not sure why everyone thinks the Brewers would be shopping Mitchell. He has actually shown the most at the MLB level of all 4 of the top prospects (Chourio, Mitchell, Wiemer & Frelick). Sure, we all expect (including the organization) that Chourio is by far the best of the 4. But after him, Mitchell has been the best. Why trade him and keep fingers crossed that Wiemer and/or Frelick pan out? If anything, at this point, I would think you could package Wiemer and Adames to try to get a starting pitcher, but even that comes with risk as Wiemer hasn't had much time yet.
I think the plan is to hang onto all 4 top OF prospects for now and let things work themselves out. Chances are we are not going to hit on all 4. If we do, what a wonderful problem to have. They may have oversigned at catcher, but that isn't a bad problem. And you can almost never have too much pitching.