I've always kept a cuttle bone in Auggie's cage - but he doesn't touch it.
I'd agree with Pedro though that if he's on a good diet like Zupreem, it shouldn't be necessary.
As for the lixit, I think they're great - but don't fill them up too much at first.
I wasn't sure how quickly Auggie would learn to drink from his lixit bottle. I filled it up, put it in his cage, and he immediately ran over to it, looked at it, looked at me, at the bottle, at me, then he pushed in the little ball and watched all the water drain out onto the floor. He gave his version of a laugh, then went back to what he was doing.