>>notok+(OP)
The American presumption of having a single middle initial has always seemed weird to me. In NL, you can have as many names as you want, and some have a lot. Others have just a first and last name. I happen to have that single middle initial, but my wife and kids have two. Also, my wife's first name is not actually any of her legal names. Same with my dad and his brother and sister. "Calling name" is a common field on some official documents for this reason.
Most interesting case I've come across was a guy who just had one name. No surname or anything. He was once questioned by police (regarding a theft in the shop he worked in) and explained that his parents were "a bit weird". He was originally American, so apparently that's also a possibility there? And apparently the Dutch system allowed it, although the police seemed to struggle with it and may have duplicated his name.