I like the middle photo with the green background (what else could I say? ), my only nitpick is that his one eye is in the dead centre of the frame, if that had been mine, I might have cropped it a bit differently in order to keep that from happening (in from the right and above).
I rather fancy the third one the most because of its warm tones, and I like the fact that Oreo's eyes are shut. Makes the shot feel more natural, because, as far as I'm concerned (based on the actions of my cats), cats sleep a lot! And their eyes are shut 90% of the time. And it's rather cute with its eyes shut, which when it's a picture of a pet, cuteness is always good HAHA. They're all nice shots, good work.