pmr post interview communication

Hey All, Dumb question but I was wondering how I should address a medical student who interviewed me in my thank you letter. "Dear Mr. Doe" seems more awk than "Dear Jon Doe". Also on top of that, the guy doesn't like to be called by his first name (he's an international student) and...

"Both the admissions panel and I very much enjoyed meeting you. Very best wishes for the upcoming Match!" Does this mean "we like you, but no, thank you"? or just a generic response or we will rank you, but not high enough? I wrote to the PD telling them they are my #1 one week ago and got...