Is trading of cats allowed, and what is the view of the four imams about it?

According to the majority of scholars and the four Madhhabs, it is permissible to buy and sell cats. There is a second view, which you mentioned, which is a minority view that says it's not permissible, but the main view of the four Madhhabs is that it is permissible. The hadith that you may be referring to refers to the sale of a cat that is a wild cat, for example, or some say that it refers to the sale being disliked. But according to the four Madhhabs, it would be permissible.