Kittens, when to rotate & food type?

I tried searching and am unclear on some things. I never had cats in my life until I got these 2 orphans at a week old, now 3.5 months old and 5 former ferals. Can you help with food questions?

*How often do you rotate foods? Do you offer different wet brand/flavor monthly, weekly, daily?

*Do you rotate dry after going through a bag, or more often?

*Is salmon, shrimp or crab considered the same as other fish in food?

Presently:
eat wet with small amount of dry left out during night. Kittens still separated from feral adults (Kittens recovering from ringworm). So, adults eat separate from kittens.

wet: Wellness, PetGuard, Pet Promise, Avoderm
dry: Royal Canin Baby Cat (takes a long time to get through a bag)
Orijen and Innova with adult cats

I order food so any type you suggest to add/change will be okay.

I would like to use preimum foods.

The ferals are the picky eaters!

Thank you for helping with my questions. I want to do the best I can for these little guys after they got such a rough start in life.

I would rotate wet foods, but not the dry. Incidentally, I think that Innova EVO and Orijen dry can be fed to kittens as well as adults - that might make your dry feeding easier. Should you switch your kittens over, slowly add the new food to prevent digestive issues.
When I rotate wet foods, I feed one type of wet food for a week, then switch to a different wet food for a week. As long as your cats appear to have no digestive issues with switching the foods, I don't see why you couldn't rotate more often

I would use one can up and offer a new flavor the next can you open - not the same flavor. I usually stack my cans in rows and mix them up so that no 2 flavors are back to back.

I've done this with my kittens and they are not finicky - they eat just about anything. I mainly stick to chicken, turkey, lamb, beef with a VERY occasionaly fish flavor. Cats/kittens can get hooked on fish flavors and not want to eat other foods.

Many times, I would forget about even buying them and the kittens would grow up never eating fish

rotatating wet daily here... dry I have two or three at once ... one main food and a cookie or treat food