My observations:
Joel is absolutely smitten with her. His body language is open, he can't take his eyes off her and he really can't stop smiling. I feel that he looks very genuine and is head over heels. Whether it be love, or starstruck or what. He was deferring to her on everything.
Carrie is another story all together. She appeared a bit bored. Her body language was completely different, she had her arms folded across her at one point, she was yawning alot and made very little eye contact with him. Not great reciprocated chemistry.
I know it was kind of intended as a joke, but when he got the lead in Hamilton and suddenly she was interested, having previously ignored his DMs for years...I felt that it was one of those truth jokes.
I felt that they clearly get on very well and have alot in common, and if he's happy to be totally owned, and she likes a puppy, then it will probably work out.
There's no way he's going to have his head turned. Not sure I can say the same about Carrie as she definitely seems less into him.