The band numbers I had posted, Y/82, were correct. The intruder was Tessa, born in 2014 at the Mississauga Holcim nest in Ontario.
However, the falcon who returned to the nest after the fight was the unbanded resident female. Both she and Ralphie have been seen at the nest. The resident female appears to be okay, but extremely stressed. I could see no sign of blood on her.
She was due to lay her second egg yesterday, but the stress of the territorial battle has disrupted egg laying, at least for now. The first egg was incubated overnight, and for a while earlier today, but has also been left uncovered for long periods of time.
Since the DEC has been involved in this situation, I am concerned that the intruder may have been injured. No updates on that as yet.
So at least for now, TPC, Tessa is not the resident female at this nest.