Good job.
I've been using that same basic method for about 50 years now but I do a couple of things a little different.
After cutting through the tail, I skin up the back a couple of inches or so...to make sure that I have enough to stand on.
then, I continue my cut along the ribs toward the front leg a bit on each side (toward the arm pits). That leaves you with a cleaner tab to grab on the belly to get the pants off.
I don't remove the head yet. I again stand on the tail while I grab that belly tab to get the pants off.
With a gut shot squirrel or with an old tough fox squirrel it doesn't always go quite that smooth but, with a young fox or a grey, it's easy going as long as they aren't shot to pieces.