I wouldn't bother getting 31 in all stats. Only in the 2 most important ones, and get ~25+ in the other relevant stats. And in order to get wish on an Eevee, you need breed it on it. The easiest way afaik is to get a male Smeargle, let it sketch wish and breed it with an Eevee. Or get a Togetic with wish, breed it with a female Skitty, which will give you a male Skitty with wish, which you breed with a female Eevee, resulting in an Eevee with Wish.
Also if you are going for a Jolteon, you might want to check out if you want a specific hidden power for it. HP Ice gives you great coverage.