> For international travel, small kids having a different name is surprisingly painful and can get you stuck in an office for hours until it's somewhat clear you're not kidnapping them

Passports have your parents name, this might cause the clerk to do a double check to make sure but unless losing you or your children documents you will never run into this. Or if you are travelling without passports (which is okay between some countries) and using documents (like birth certificates) in different languages