What is interesting about that +gregory response is that it appears he no longer considers ambrose a bishop(despite the "papers"). And, I wonder if the title "fr." in orthodoxy always means priest like it does in catholicism. Because, he calls him "fr." because he was tonsured a monk. And, ambrose was tonsured before he became a priest. So, I wonder if he doubts his ordination as it appears he does his consecration. I am filling in blanks and assuming. But, that is how it appears.
In Orthodoxy, a monk and a priest are both called "Father".
A non-tonsured monk is called a "brother."
If a married priest is defrocked, he is returned to the lay state.
If a priest-monk (hieromonk) is defrocked, he is returned to the status of a monk.
If a bishop is defrocked, and this bishop was previously tonsured as a monk, then he would be returned to the status of a monk.
However, if a bishop was never tonsured as a monk and he was defrocked, then he would be returned to the laity.