Just remembered a situation I had a few months ago. Similar scenario. Changing recepts in bath. Gfi breaker feeding baths. Tripped breaker, changed recepts, reset breaker, no power! Tested breaker and it was ok. Searched for gfi recept that mght feed baths, nothing. Looked all over house. Eventually found outside recept was also on circuit and was also dead. Pulled out recept and found backwiring was just loose enough to cause trouble.
