Keep Rain Dish on the sun cruel, it is debatable that Liquid Ooze is useful but having Rain Dish is without any doubt great against rain. If you were using Kingdra on a non-Rain team I'd hope you'd use Swift Swim on it.
I agree that Suncruel should be OO, it's very uncommon and pretty simple to throw together using the standard sets. This may sound odd to some but I would throw T spikes in there as well. There are really that useless, if Alkines short explanation isn't pleasing enough I'll be glad to expand.