About dividing, are you sure it's okay? I'm thinking Plagueis has gotten very used to his large place. :P I don't have sand as the substrate for the cories, but are they "easy" pets? Not that I can't take care of them, because I can, but what I love about bettas is that you don't need to worry about them as much as most other fish.
Do nerite snails get very big? I don't want that. :P And I don't have much algae which is the problem.
And the word you're looking for is "brackish" and thanks for the quick reply!
1 Dwarf Gourami - Balin
8 Neon Tetras