Is this tank alright [repost]?

Thanks for reading. I am getting a 20 gallon aquarium with medium sized, smooth gravel, a large ornament with 3 or 4 holes and lots oh hiding cover. there will be a few fake plants and a few real. I am using a Top Fin 20 filter, a heater, and a hood with light . There will be 4 red wag platy (all male), 3 Peppered Cories (all male), and two mystery snails- 1 black 1 gold. Any suggestions?