i'm not really an expert and all, but I think this vaporeon will work ( based on my observations with the other answers)
( nature and ev spread is all on you, 'cause I don't really think that it's that important)
surf- high 90 base power and, in double or triple battles, it can hit all Pokemon in the field (which serves as an advantage and a disadvantage)
ice beam- it deals with ice, it has a high base power and it can freeze Pokemon
shadow ball- takes care of ghost and psychic, plus has 80 base power
aqua ring- can heal vaporeon and takes advantage of vaporeon's base hp
the item I will recommend for this kind of moveset is life orb. its so obvious because when vaporeon first sets up aqua ring, the life orb recoil will be reduced.
please try to suggest things that will improve this answer.