the spend the least amount of time together, we hardly see them and when we do see them together they have zero chemistry

Pocahontas/Smith have least chemistry than other couples imo. Snow/Prince look cute together but they recemble two kids playing romance so there isn't much chemistry there either.

I think all the couples have some chemistry between them. Snow White and the Prince meet so briefly. I think he sought after her because he liked her and saw something in her that he could love. To give up on her would be wrong and not in his nature. Cinderella and Prince Charming meet so briefly as well. They both see something different in each other. Cinderella is the girl he had been waiting for. And to Cinderella it was all like a dream and she never thought she could have her dream. I think both couples have chemistry but not as much as the other couples who had a longer time together.

Well we never get to see them together for much time. They seem happy and in love but they never even have a decent conversation together, so how will we even know if they have chemistry? There doesn't seem to be a whole lot going on between them in terms of chemistry. Mulan and Shang don't have much either, but hey, at least they had a few decent conversations and got to know each other.