First time helping someone with their team so here it goes:
If you're looking for a nice rain dance setter than I would suggest going with this bad boy:
Klefki
Ability: Prankster(this is its standard ability so you won't have to hunt for it on safari)
Item: Damp Rock (so you get those 3 extra turns of weather)
EV spread: 252 HP, 128 Def, 128 SpD
Moveset:
Rain Dance
Foul Play
Thunder Wave
(last move is user choice, but I would recommend either light screen or reflect)
The whole point of this pokemon is that more times than not you are definitely going to be able to set up rain for the rest of your team. With prankster it now gains +1 priority to all non-damage dealing moves (i.e. Rain Dance and Thunder Wave) so against most pokemon it will be moving first. Should that not be it has fantastic typing in Steel/Fairy which only nets you two weaknesses to Fire and Ground. Foul Play is your main attack move; you lose out on Prankster Priority, but instead gets the ability to use the attack stat of its opponent which is quite useful in mitigating klefki's pitiful attack stat. Overall you end up with a fairly bulky setter and gives you a chance to play around with the movesets of Zapdos and Vaporeon to better cover threats you might encounter.
Hope this has been helpful to you!