I am asking two questions in one. So here is the first one:
How much happiness does Eevee have to have in order to evolve into Umbreon?
Second Question:
If my Eevee evolved into Umbreon, would Return's attack power be 110?
I got the number 110 from here: http://pokemondb.net/move/return
I also gave my Eevee the Soothe Bell if that helps.