|This is a frequently asked question about relationships and VOCALOID characters.|
Relationships are not defined on Vocaloids in most cases (Sonika is the only one to ever list other Vocaloid relationships to herself via twitter).
Kaito was made to be the male counterpart to Meiko, hence the similair names to each other and both were from the original Vocaloid software. They are not linked to Crypton's later CV series.
If you read otherwise then it is purely a fan interpretation or a error.