In Japan no one has any middle names unless you are Catholic and given a baptismal name or something (but it probably won’t be on the document and is not an official part of your name) or you are from a different country where people have middle names. So basically, people have a family name and a given name and that’s it. Usually people present their given names with kanji just like most family names are written in kanji. There are exceptions of course. Some parents prefer their children’s names written in hiragana. Sometimes names in hiragana might go well with certain family names. But generally, hiragana are seen as soft and feminine characters and people seem to like names written in hiragana for that reason.
Meanings of names can be different depending on which kanji people use. For example, my name in roma-ji is Risa but I would write it 理沙. However, if my parents wanted to, it could have been 里沙, 梨紗, 理佐 or even りさ if they liked hiragana so much. They are all Risa. As you can see, the use of kanji really expands the range of possible spellings of names.
When parents are thinking about names for their children, they seem to look for names that have nice sounds. So, at first, they might start with jotting down names in hiragana and later on think about kanji to the names. The number of strokes is also a big factor of deciding which names and characters to give to children. It’s superstitious, perhaps it might not sound modern to you. However a lot of parents still seem to care about it. I don’t know how it works, I looked at it briefly now, it’s quite interesting but very, very complicated… Basically, it’s a kind of fortune telling. The number of strokes can tell your future, so parents try to come up with names with good numbers of strokes. There are various interpretations for this, which mekes things even more complicated…
