Follow up after receiving SA offer?

Received an SA offer with a BB 2 months ago - obviously feel v excited at this. During the interview process, there were few people who actually pushed me through and I'd say I owed this opportunity to them.

My question is: before the matching process, is it ever appropriate to send them a follow-up email, just saying how thankful I am? i.e. "happy holiday" kind of email? Trying not to cross the line.

Thanks!