So Ritcher is a feisty little boy! When he bites you yelp. Or hiss. Grab him by the loose skin over his neck, shake not too hard / gently and say NO! That gives him the idea it is very much not appreciated. And is the human version of what his mother would have done.
He probably needs to be castrated soon! He's about that age where their hormones kick in and he'll turn into an obnoxious tomcat. So that might be the reason for the pulling and weird noises. He looks small for his age so ask the vet when they want to do the surgery.
Orphan kittens are often naughty because they never learned their proper cat lessons. They'll outgrow some of it but he probably won't ever be quite "normal". Just keep doing what you're doing and it should sink in eventually.
So very sorry to read this news. You did your very best for the little guy. We invite you to post a tribute to your kitty in our Crossing the Bridge forum if you'd like. We'll lock this thread now out of respect for your loss.