I made some modifications to the sketch, at the request of my commissioner: smaller ears (I went with the sort of tufts that owls have), all four cat feet, and tailfeathers on the tail. The tailfeathers need work, but this is still very rough.
The colors are just to get a feel for how the contrast in this pic is going to work. Light-colored animal, dark background. I think I want the background to be even cooler, more toward blue than green.