Will Smith spent all of 2019 with the Dodgers, caught 46 games. Then in the COVID shortened 2019, caught 34 games. Doesn't appear to have affected him.
As long as Moreno catches at least 40 games, or 1 or 2 games a week, that should be sufficient to keep his mechanics sharp. The other part of catching, the game calling, batter tendencies, etc mostly learned outside the game?
I don't know how Kirk will get much or any time behind the plate, after Moreno comes up. Will be interesting to see how it is handled, and if Kirk shows up to camp 30 lbs lighter, it gets super interesting. A trade seems inevitable.