I dont think it would be a problem, the ones used to it, just might kick up a fuss for awhile, but in time they'd be fine. As long as no one has tendencies towards UTI's, my vet told me that one of mine that had a UTI should have some wet food as well as free available dry. She gets one pouch of wet food a day and the others are not even interested in it.

I feed mine two varieties of Royal Canin. They're all persians so they get that specific food. I had been giving them Temptations and Whiska Lickin's for treats but noticed after a few months a big tartar buildup. I fooled them, I put Royal Canin Oral Care in the Whiska Lickin's containers and lo and behold, no more tartar.

That stuff works.