Woman covering the feet in salaah

Q: Is not covering the feet below the ankles for woman against sunnah? I have severe waswasa and I found out that except for Hanafi's, others consider the feet as awrah. Are my prayers invalid as I didn't cover it after knowing about the ruling. Why do Hanafi's not consider the feet as awrah. I feel scared that my namaz isn't valid. What should I do?

Filling the gap in the saff if the muqtadi leaves during salaah

Q: There is a rule in Bahishti Zewar that it is makrooh to stand alone in a row. The person should pull a person back from the row before him. What happens to the gap formed by the exiting of the said muqtadi to fill the previous row?

If a Muqtadis wudhu breaks during prayer, should he just leave and leave a gap in the saff? What should he do in this regard?