Neck cracking is risky. I'm not sure any other normal type of cracking is risky for a healthy person.
I'm not sure. An orthopedic surgeon who was treating me doesn't think neck cracking is any sort of big deal, but I have a narrowed spinal canal, protruding disks, and I need surgery on my neck. OTOH, nobody thinks cracking has anything to do with it. Maybe I cracked my neck trying to relieve the problems I'm having, who knows?
OTOH, I've cracked my fingers, elbows and spine very often. I have a bad back now but I seriously doubt cracking had anything to do with it, especially since it is my thoracic spine that cracks most. (usually over the back of a stiff chair that hits my back at just the right height.) I find that as I get older (I'm 58 ) I can't crack joints nearly as often.