I don't think King's Rock stacks with moves that already have Flinch chance. I would give your Crobat the Wet Rock, which increases the amount of time Rain remains up after a Rain Dance. It definitely seems beneficial, since your Crobat's plans seem to be to set up Rain Dance and switch out so other Pokemon can really take advantage of it. Alternatively, some kind of healing item might also be reasonable.

Don't use Expert Belt on Vaporeon, use Leftovers or another healing item. It really increases his bulk significantly. I also suggest you train some Defense, as those stats really do help. You seem to have capped HP, but what you really need is those Defense EVs. I love Vaporeon, it's quite a good Pokemon, but it is not for killing things. Scald is there to inflict burns so you can stall people to death and never die to anything ever. Part of the reason I dislike Toxic on Vaporeon is because Scald and Toxic don't mix very well at all. Toxic does fit the playstyle, though, so if you like Toxic use Surf. I prefer to use Scald and another move like Haze, Aqua Ring, or Protect to help you out. I would only use Protect if I had Leftovers, though. Another option if you want some increased firepower is to run Hydro Pump, which in the rain has some massive firepower. You can also run Rain Dance as your last move, which I strongly suggest since it allows your Vaporeon to set up the Rain for itself.

Now Jolteon is a Pokemon that wants Expert Belt. Increase that ridiculous damage output to score some key KOs. You don't need to train Jolteon in speed much anymore, as it has one of the best Speed stats of any Pokemon in the game. There are very few things that will outspeed you without help from stat-boosting attacks or Choice Scarf at your current Speed level. Feel free to train some HP instead.

I don't want to suggest any ridiculously massive changes, but it seems like Crobat is really not very useful on this team and you could do much better. For one, having a second Electric-weak member of your team seems poor since it's such a good attacking type, and there are plenty of better Pokemon for setting up Rain or taking advantage of it. A Steel-type of some kind, for example, would be able to use it to great effect, resisting Fire-type attacks slightly better. Toxicroak is also a great choice if you can get it, as Dry Skin is awesome. I'm not really sure what's available.

It seems like the computerized enemies land special effects more often, but I think that's because you are fighting so many of them that statistically, you are bound to run into their status effects often enough. I think if you went for enough times it would closely match the actual percentage, but with a small sample size it will definitely seem that way. Like, I can't tell you the number of times I've missed with Leech Seed, but that's because I've used it like several thousand times, so even with a 90% hit rate I'm bound to miss with it eventually.