I've been on and off T twice, though not by choice. In my experience, when one goes off T, periods return within 3-4 months, facial and body hair diminishes exponentially, muscle mass diminishes, and fat goes back to female distribution. Voice remains the same as when on T, though I know sometimes it can revert somewhat... I watched a documentary on Thomas Beatie (the "pregnant man"), who said that after a few months off T, his voice was at least an octave higher than when he was on T. Of course, I believe he also had to go on estrogen and progesterone for a time before becoming pregnant... and certainly had more of those hormones while pregnant.
Clitoral growth, as far as I'm aware, is permanent. Mine didn't diminish in size any. And since going on T, my "lubrication" of those parts has actually increased about fivefold. That may be due to my increased ability to become aroused... not really sure.
I assume facial masculinization would be permanent, too... though that fat redistribution can make quite a change in the face as well.
SD