Hi Stace,
I am only new to Axolotls myself, so have put my tank together based on what I've read and seen in pictures.
The snails haven't touched my Axo, they just wander around on the glass and ocassionly fall off. They were in the same tank at the pet store so I assumed it was ok. The label on their tank just said "Golden Snails". After I read what other people had said about snails I've kept a close eye on them, but it's been a week today and haven't had any problems.
I use a fine aquarium gravel, I couldn't tell you the exact size.. but each piece seems to be about 2-3mm or smaller. I've been hand feeding Ebon so haven't had any gravel eating problems.. the new one (still unnamed) tried to eat a couple of bits but spat it out, I think this gavel would be to small to cause any damage anyway. But I'll be keeping any eye on him until I can get him to feed from my hand as well.
The plants I have are called Pennywort. It seems pretty hardy. So far I haven't had any problems, I have them pretty dug in though. I did try another plant, and it didn't last at all.. (not sure what that one was called)
I wasn't sure if the tank was too bare or too crowded.. I guess it's a matter of trial and error. I will try and keep an update on how the plants go.