I do not own One Piece !
Here's a theory about;
Subject: Family ties in One Piece.
Source/Inspiration: One Piece in general.
Theory: So, the family ties in OP are QUITE complicated and shady, we never get to know everything and a s soona s we think we know something it is blown up in our faces. And we love it. But I still have a theory!
We'll start with Brook and Kuzan (Aokiji, one of the three Marine Admirals); both is tall, have black and curly hair plus is perverts. Remember Aokiji's comment on Nami's rack.
And then we have Usopp, with the same hair but no height and nowhere near that amount of pervertness. He could be related to the Square Sisters, Mozu and Kiwi, since they got the same kind of hair and noses. Probably on his mother's, Banchina, side.
My favourite mob- I mean... Giraffe Kaku could also belong to that side of the family tree. But he's more like a distant cousin, he's nose is square. But that might mean that he's more realted to the sisters than to Usopp.
That's it for today folks! Review if you feel like it!