Is the Mufti's statement correct, that Abu Hanifa says a woman's feet are not awrah because they usually appear, like the face and hands? And what is the most authoritative opinion in the Hanafi school regarding a woman's awrah?

The Fatwa (definition)'s Summary:

The preponderant opinion in the Hanafi school of thought is that a woman's feet are not considered 'awrah (private parts that must be covered) during prayer. There is disagreement among them regarding whether they are 'awrah outside of prayer. However, the ruling adopted by us is that a woman's feet are 'awrah both inside and outside of prayer. According to the Hanafis, there is no necessary correlation between the view that a woman's feet are not 'awrah and the permissibility of looking at them.