I know that corn on the cob shouldn't be fed to Tortoises, though I thought that baby, miniture corn was okay to feed to them.
The main thing she eats the most are weed leaves, dandelions and lamb lettuce.
Good to know she's getting most of the right things; the corn will still have to go. Sorry.
I think the water dish is fine too and she can fit into it well.
It really isn't. She can't bend her body, like other reptiles, which means it's a flipping hazard. I know those bowls are expensive (I had to return the one my husband brought home!). At the price for a replacement saucer, however, most experienced users wouldn't take the risk.
I'll let the others help with the lighting and humidity. Our grown Russian is entirely outdoors, except for hibernation, which means I don't have to fuss with the more difficult things.