I ended up having a lot of trouble with the pattern. It calls for essentially knitting short rows in order to pull off intarsia in the round, but it just never worked right, and left a lot of holes and weird stringy looking places. Instead, I decided to just duplicate stitch the stripes and tummy on. There were some issues with the muzzle, too, mostly that there's no indication in the pattern which side of it goes up, so I spent a while pinning and repinning trying to get it right. Protip: it's the smaller side.
That said, it still came out looking pretty good, so I can't complain too much. Yay for excellent Halloween costumes!