Rice in an omelette? I've never heard of that.
A friend of mine from Jennings always puts rice in her scrambled eggs. I've never had it, but she swears by it. I'm not sure what the effect is, though.
Onions and potatoes are about as far out as I go and not too often. Usually, it's just chives or green onions, but I don't eat them often. I'd just as soon have scrambled eggs with the same ingredients.