One more question about EVs

[DarkFlareon]

OK, if I catch a Legendary or I get a Lapras from the guy, or get the Eevee. Do they already have EVs or do I have to breed them to get perfect EVs?

[Dan the Pokeman]

Whenever you get possession of a Pokemon by breeding, catching it, or an "in-game" trade, it won't have any EVs. You must train the Pokemon to gain EVs.

IVs are determined when you take possession of the Pokemon, and will be random. It may have good IVs, but you'll probably have to breed to get a Pokemon with good IVs.