The clumping is the only one I find controls the odor. My cats have never shown any inclination to eat it, tho the dog has. I keep a kiddie gate across the door to keep the dog out.
Just a word about the covered litter boxes; I got one and soon discovered my cat peeing on my bed and pooping on the floor. Took me forever to make the connection, but once I did, I tried putting her in the covered box and saw that she was absolutely NOT going to go in there. Once I removed the lid, she immediately started using it again and hasn't gone on my bed one time since.