Go Jolteon, Espeon, Glaceon, Umbreon, Leafeon, and Vaporeon. But I will give suggestions on all of them anyway.
Jolteon: Go Life Orb. It's fast enough to set up a Magnet Rise if you know what's coming for you. Replace Volt Switch for it.
Glaceon: I would make it a little more bulky and a little less speedy. Change the EVs in it. (Keep the SAtk EVs, tho.)
Espeon: Perfect. I wouldn't want Grass knot, But fine by me if you wanna keep it.
Leafeon: Switch up the Speed or SDef EVs with Attack, needs more attacking power. Iron Tail to cover annoying Ice types over SD and give it Choice/Muscle Band.
Umbreon (Troll): I wish this thing could learn Will-O-Wisp. You're good with this. Moonlight, Payback, Curse, Protect.
Vaporeon: All good, Keep Scald.
Flareon: Ok, this thing just doesn't fit into the eeveelutions group. I don't like it at all. Everything but Dig is good.
Eevee: Well this thing does not fit here. I ran calculations of stats, it's just not strong enough! I'd rather have an evolved Pokemon than that.