Usually just white. LOL Sometimes they will grow red splotches too. Some will have black, red, yellow or even white eyes too! I think the all white is pretty rare though.
Just depends, you can usually tell by the colour of the parents, if there was one white and one orage / red parent it could turn out any how, may be a mixture of both, its nice to wait and see though.
Midas/RDs grow as fast as you feed. Some guys like to feed them 2-3 times a day. At that rate, I would guess 1/2" per month. I feed my little guy 1-2 times a day. Small amounts but enough to make his belly bulge. I don't want him to grow to fast yet... I have limited tank space.