Since you are using fun fur and the stitches won't show anyhow I really don't see why you couldn't just use all knits. You'll get garter stitch which isn't going to curl like stockinette. Just my 2 cents. Others, more experienced, may have a much better response.
Cheating is an option. . . . Cheaters never win and winners never cheat, but smart knitters who want to retain an iota of sanity do, cheerfully. ~~Kory Stamper