On casual with item usage, i think a team of 6 should be doable. I agree with the alolan muk choice, or generally anything you feel can lay down spikes. Id personally suggest noivern. Im pretty sure you can catch a noibat fairly early, and while its pretty much dead weight till it evolves, it does perform really well after evolving. Tailwind support is really nice and a fast mon. Another pokemon that i have found really useful in Rejuvenation is contrary Malamar. You get one not too late and is capable of carrying out some sweeps, and is honestly a pretty fun pokemon to use. It may clash with your espurr typing though.