On Jolteon, I wouldn't put it on that tier. While it has good offensive stats, its movepool is not good at all, in fact, it's terrible. The moves he can use consist of Thunder (bad accuracy), Discharge (not as strong as T-bolt, which is unavailable as a TM currently) and Shadow Ball. Those are literally the only special moves that have a decent base power for it to use. Also, I'm not counting HP Ice because it's not easy to get, you'd have to breed for hours praying to god that you get lucky enough with the IVs. If you really need a good electric type on your team, either go for Magnezone or Manectric (assuming you breed to get Flame Burst, since Flamethrower/Overheat aren't available yet :[ ).