We New Englanders of long term (i.e. from 17th C) have the same onomastic habits--somewhat less using surname as prenom (though my mother wanted to do that for her youngest son), but certainlyfamily name as middle name. I caught a lot of social flak as a 1st grader (girl) for this. In fact, I questioned whether my sweetheart would be a suitable husband for me-- because his 2nd name is not a family name, but a "Christian name", --although that of his umpteenth grandfather a Boston area 18th C deacon