Re: Dream World Abilities
Dream World abilities can change when Pokemon evolve if the next form can't have that ability.
Dragonite's hidden Dream World ability is not Marvel Scale, but Multiscale. So if you evolve a Dratini with Marvel Scale into Dragonite, the ability will change to Multiscale.
I'm not sure about the best DW ability, but I think Bulbasaur with Chlorophyll is awesome!