Is this a good 10-15g tank setup?

No, all of those fish require 20+ gallon tanks besides the snail. Mollies are social fish and prefer to be in a group of 3+, neon tetras need a school of 6+ and are very sensitive to water quality, and oto cats need to be in a school of 4+ and are also very sensitive to water quality. Some good fish for a tank size of 10-15 gallon would be guppies, dwarf gourami, bettas, kuhli loachs, pygmy cory cats, galaxy rasboras, white clouds,platies, endler livebearers etc.