I was thinking depths too. On Hard! (Makes it more worthwile)
I'll bring Lucario, Cyclohm, Then 2 of Donphan, Scrafty, Serperior, Machamp and Cinccino (espescially if multi-hit moves don't count for deafening screech)
Nidoqueen*, Klinklang, Arghonaut, Cyclohm, Milotic, Tomohawk, Voodoom, Blissey, Ferrothorn, Lapras, Krillowatt, Golurk, Rotom-C, Gastrodon East, Magnezone, Revenankh are all plausible for you, so choose the best 4 (Deffo Blissey)
I might also suggest rotom wash, and Trick room (Maybe just paralysis, we have multible twavers) and Rain (Thunders and Boosted Water moves will be good for Aero espescially)?
Also water gun will be very helpful, boosting the power of electric moves, and being usable with deafening screech.