Why would Larnach or Celestino need to be DFA'd? Both have minor league options. Larnach needs to show he's healthy, and Celestino could use some more time in minors. St. Paul should have a starting outfield of Larnach, Celestino and Wallner with Garlick at DH.
Vets and guys without options start with the big club. Someone will probably, although hopefully not, get hurt. Someone may not take advantage of their opportunity and then be passed up by someone who is performing.
Don't sell low. None of the outfielders are slam dunks with nothing to prove, but they all have upside or at least above-average skillsets in different parts of the game. Let them battle it out and then the trades or DFAs can occur during the season when the cream has risen to the top and the occupancy in the trainer's room becomes a familiar look.