EduDevelopmental

I had been in contact with a POI at a program and in all honesty, had received signals that he was pretty excited about working with me (may obviously now be mis-perceived). After interviews, I sent a thank you and he responded, then we had no more contact. Prior to that, was also in contact with several faculty, who were warm and communicative. I received a generic rejection through the school's portal today. I was a little surprised by the impersonal-ness of the rejection, given how communicative the faculty were. But all good. I guess my question is: Is there etiquette around reaching out to POI after this, just to say thank you, or to sort of "close-out" communication? On a more self-interested note, is it ever appropriate, if I had a relationship with POI, to ask for some sort of feedback (or at least a more "personal" rejection or indication, so to speak)? Thanks in advance.