I see no reason not to let the people we have play out April. All of Kottaras, Bard and Brown have the upside to be interesting as catchers, with Brown as the guy who probably should win out and Kottaras and Bard as the ones who probably will.
I think Kottaras is somewhat underrated here. He had a pretty good offensive season (.804 OPS) and the big knock on him offensively was a low AVG. A player CAN succeed with a low AVG though and Kottaras has the power and patience to be that kind if player
While the comparison isn't perfect, Kottaras' 2008 AAA campaign resembled Mike Napoli's 2005 run, although with significantly less power. Does that mean that Kottaras is a poor man's Napoli? Hardly, since it was only one good year and Napoli is probably better defensively, but Napoli demonstrated that a low batting average in the minors is not an automatic bar to big league success for power hitters and a guy who bears some resemblance to him should be given a chance to show what he can do in the big leagues.
I think Kottaras will pleasantly surprise us. Who knows? Maybe in 5 years we'll be singing David Wells' praises like we have for the past decade with Heathcliff Slocumb.