And to answer your final question: Thank-you notes are never amiss, but ordinarily should come from the parents.
As part of Beliefnet's "Religion Etiquette Q&A" column, we occasionally include useful posts by our members. On the message boards, member BlueLotusPetal asked how to behave when meeting Buddhist clergy:
I am going to be introduced to a local Lama at his home in an informal setting. How should I address him? Do I shake hands? Bow? Should I bring a gift? If so, what? What else do I need to know as far as behavior, addressing him, etc. Member sanath answers: The etiquette will depend on the tradition of the temple. Basically in all the traditions it is courtesy to put your palms together in gassho. Member hol1 answers: Dress casually, bring a small gift (how about a small basket of assorted teas) if you want, and just say "Hello, Tashi Deleg...." Follow the others' lead and by all means say "Thank you" after the class. Speaking of a more formal setting, member little-tara says:
"My Lama, who is an American woman, has not placed a great deal of expectations on how we dress when we are with her, but when we went to a teaching by Terton Namkha Drimed she suggested we dress as if we were going to meet the Buddha. And as women it is culturally appropriate to be cover from the neck to the elbow on top and then pants or a long skirt/dress."