Not many platys will probably suvive. I have platys in my 40 gal, one male and 3 females. One female did have some babies twice in fact but none survived. It's weird but only the one female ever gets preggo, neither of the other two. Unfortunetly I wouldn't keep more than 4 platys in a 10 gal.
As far as the snails they probably came from the live plants. They are really hard to get rid of, and will over run your tank very quickly. Also watch because they can get out through the smallest holes in the lid.
Jackie and her little babies.
Candi- Italian Greyhound
Cash- Italian Greyhound
Jasmine- Tabby cat