Never had a sorority before, but here's a shot.
Play with this to see your stocking options
You'll probably need a LOT more plants - and this means pretty darn tall ones, too. Maybe not too overboard with plants, but again, never did a sorority before.
With the pellets and feedings, you'll have to experiment with that and learn each betta personally to see how they eat and stuff. You eventually just learn how to feed them successfully, etc. I feed mine two pellets per meal, so see how that ties out for you. Good luck!