Absolutely take them all off dry, that would be the best. There is no good reason to feed cats kibble. It doesn't have an appropriate amount of moisture, it doesn't have appropriate ingredients, and it does nothing for their teeth (in fact, it may actually
cause dental problems). Dry food is actually responsible for more feline illnesses (diabetes, inflammatory bowel disease, kidney disease, bladder and urinary tract problems, obesity, allergies, etc) than pretty much any other factor, and since your cats already eat wet food, you're ahead of the game. Lots of info here if you want to know more:
http://www.catinfo.org/