Okay. I dont have either springtails or isopods. Are they necessary? How do I clean the enclosure from their poop and slime?Nice, they lay tons of eggs. Yes they will eat eggs and meat, but I'd probably not just because that can become a smelly mess fast. Another thing, try not to let springtails in your bin, the small silver ones aren't a problem, but the larger white ones annoy snails by climbing all over them. I like zebra isopods for clean up if you have any, they are slower and not as likely to eat the snail eggs(as other isopod species).
Quinoa, oats, seeds, bee pollen, spirulina, nuts, alfalfa, sprouts, beans, etc all should work well. Along with greens/veggies/fruits and a calcium source available at all times.
Snails are omnivores and eat pretty much anything. Protein and fat rich foods, with calcium, will help their growth more though being higher in calories and nutrients. Think of it like this, will you gain more mass eating a steak with a glass of milk or a salad with no dressing? The salad is good for all of the micronutrients, but it doesn't help the body build as much(though there are a lot of minerals in plants, many aren't as well absorbed... in people at least).