Never heard of many cichlids eating snails myself.
Your tank is overstocked already, and Tbar cichlids would not be a good choice, none would be a good choce really until you rethink the stock list on that tank. Not to mention the species mixed in there together could use some looking at.
I'm really not sure how you've been doing it this long with "Silver Dollars, Rams, Gouramis, Bettas, Cory's, Gobies, Tetras, Angels, Killies, and soon some P. pulchers" all in just a 55gal tank. It makes me cringe to tell you the truth.
Its also odd that you would rather cram the cichlids in with other community fish in the 55gal while you have a 75gal with just swordtails?