My worthless guess is that when rosters expand from 26 to 28, they'll take a pitcher and a position player.
I would think a Kelly trade makes a Dingler promotion all but certain. That's a one for one swap. But if they don't move one of Kelly/Rogers, I'm not sure I see them rostering a 3rd catcher.
I'm not sure I consider Carpenter a young player that needs to be seen in terms of performance. He probably still has a little bit of growth yet, but I think he's a MLB player. Meadows definitely needs some MLB time. Well, his bat does. The glove plays, no worries there. If both do return this season, the roster decision could be interesting. Do they dump someone like McKinstry/Urshela, demote one of Villade/Malloy? Probably too early to tell.
On the pitching side.... yikes. Jobe is the next fun thing, but does he earn a late season promotion? Or do they just pull up someone already on the 40 (which, meh).