Today (Sat.): Go to Joann's, buy materials and craft supplies and get the fabric washed.
Sunday: Make the tail and ears. These are the most critical parts and I can't buy the kind of tail I want. I'm using this tutorial to make the tail and the ears (the tutu is adorable, but it doesn't exactly go with the theme of being our tuxedo kitty).
Monday: Trace t-shirt and leggings patterns and cut out fabric. I'll be using the plain t-shirt (no peplum) and leggings from McCalls M6780.
Tuesday: Sew up the t-shirt, check fit.
Wednesday: Sew up leggings, check fit.
[Edit: I originally wrote that Friday was Halloween, but after posting, I was talking to my DH and realized that Thursday is Halloween! It's even sooner than I thought!]