I would put Ludicolo over Empoleon. Give
[email protected]/Leftovers: Leechseed/Surf/Icebeam/EnergyBall
Stealth rock give it to swampert. Cursepert this Gen isn't as useful anymore, even after chesto. While u snooze the second time, your opponent can throw in sword dances or nasty plots. Give
Swampert: StealthRock/Earthquake/Waterfall/Avalanche or Stone Edge
As for grass moves, you should know who carries em and who doesn't.
And also, why make a water mono team when you have no rain dance at all in there? Rain dance is meant for water types. Abuse it.
Milotic also makes a good opener as it lures out something that has electric/grass attacks, of which it can use hypnosis and put it out of battle, giving your mono team an easier time.