In my experience its a little more complex than always having lots of hair or not in lion scat. Having said that, a lot of cougar poop that I've seen does have hair in it in varying amounts, sometmes a lot. In the Pacific NW it is usually deer hair. Would be curious to hear Steve Craig's comments.
Bobcat often has some hair, or bits of feather sometimes, but it depends on what the cat ate. We have salmon runs when some animals, like bears, eat almost nothing else for several weeks. I assume bobcats eat a lot of salmon when they are in the creeks.
Animals eat so many different things that they produce a wide variety of scat at different times of year, so different in colour, size or texture that it has fooled me more than once. Sometimes in spring our deer leave miniature cow patties.
Also have found places where lions make scrapes (and often leave scat) and keep doing it in the same place over several years.
There sure is a lot I don't know but it is fun to keep learning.