Nice pics and shooting of the squirrels.
Concerning the coyote. I never use any of my .22 caliber air guns for that. They are just not powerful enough unless you are at 10 yards or less and can hit the yote right in the brain. Otherwise, I wouldn't take the shot. If I was using my .25 caliber Eun Jin Sumatra 2500, I would try if I was withing 40 to 50 yards, but once again, I would have to be sure I could hit it in the head. By shooting it in the back, you probably poked a hole in it and it will be injured, but most likely will not die (at least not from trauma, perhaps from lead poisoning

). Perhaps it will not come back now.