Need some guidance with my 11 month Catalina

Hello everyone. Maui has begun the process of molting his baby feathers (started about 1.5-2 weeks ago). I expected him to be moody during this process since I would be too if I had all kinds of things popping through my skin. His scarlet background is definitely shining through though and I'm not really sure the best way to approach his moodiness.

For starters he is definitely getting nippy and the bites are starting to hurt. I don't pull away but I definitely do grab his beak and say no (maybe this isn't the best approach? Especially since it doesn't seem to be doing much). He's obsessed with biting hands when he's on your arm. And he has this thing where when he is on the floor he will grab your hand with one foot and half roll over and be in his back, but clamps down on your hand and won't let go.

He's also not listening as well and today was the first day that he would not step up on command and actually tried to bite me instead. He doesn't scare me and I don't back down but I'm conflicted as to how to best approach and correct this behavior as well. I'm assuming him molting is playing a good part in this but I would still like some help in how to correct these issues.

Thank you in advance!