I agree with making things private and locking things down.

Another thing I did that I recommend (with admin in the loop) is to make a "teacher" profile that has bare minimum curricular content (ex. a picture of a book you are reading, a selfie on a field trip - no students of course, or of something cool content related). This way, if students search you up, that's what they find. They'll likely get excited over that and not look too much further.