Here's what I'd do with the team that we have moving forward:
Keep Mereiles, Gareffa and Mascherin together.
Move McHugh up to play with Henderson and Darby. Any of the three can play centre and all of them have a pretty decent record on draws for people who play most of the time on the wing.
Put Bunnaman between Carter and Damiani.
Put Schiemenz between Seitz and Guest.
I'd like to see Mereiles on the first PP unit in place of Damiani. He can dig out pucks in a way that Damiani can't. Damiani has no goals and one assist in his time on the PP, so best to shift him to the second unit. Carter has seven PP points, so he might get a look as well.
For D pairings, I'd stick with Hora-Roberts and DiPerna-Villati and put Burns beside Gentiles/Peterson.