I'm not sure what you mean by "crawling skin" but you do itch like crazy. It is caused by the skin streaching and the added blood flow in the body.
No
Of course it's normal, and expected!
Yeah, usually their ears.
Sometimes people are hungry when they twitch. Other times, they might ve trying to fall asleep. Some people have disorders that make them twitch too
Yes. Every puppy does it, it's completely normal.
People twitch during sleep due to involuntary spasms in muscles. The movement, if it does not become bothersome, is normal.
If it is a siezure then they will shake a little bit and their eyes will flutter.
While they are sleeping? Yes, they arejust like kittens and puppies they have little 'dreams' that cause them to twitch and mew.
Slow twitch
Fast twitch fibers
Yes. Like humans, animals dream and twitch just a bit while they sleep. Perfectly normal.
You can get a twitch from stimulation or damage to the muscles.