Foxtrot
Yes foot pounds are up there and speed comes into play also. They both can do a lot of fur damage on a fox. The problem is you are trying to cover both ends for fox and coyote. I will put up with fur damage, I am not in it for the fur price lost. The 22 hornet is what people like for fox, but is a little light for coyote at 200 yards. I think I read 10 lb for every pound of animal is a minimal. A 40 coyote needs 400 foot pounds and a 11lb fox needs 110 ft pounds. All this is with a good kill shot. A marginal hit and you will have a runner. I could be off some, but who knows any of this stuff as fact. But it is what I feel works as a minimal when I am looking at a bullet.