Building a Mono Water team for some fun, any tips for improving it?

Mono Water Champions

I tried to cover Water's few weaknesses the best I could, fortunately Grass isn't a very popular type right now.

Swampert is going to do Swampert things, and because 2 of my mons are immune and another doesn't mind EQ I decided to add it.

Blastoise is my backup mega with Water Spout for big damage.

Pelipper is my weather setter and Flying type, simple enough.

Rotom is my speed control with Electroweb.

Basculegion will be doing Basculegion things, don't need to say much else.

Araquanid is an insurance against Grass types, while also being able to hit like a semi truck with Water Bubble Rain STAB water attacks.

Im considering changing some items, but I'm not fully sure how to improve it from here. Any other Pokemon suggestions would be appreciated.