Most of those "Jacoteys" on FB aren't really Jacoteys but rather Alizée fans.
Alizée does have a big family, but if I'm not mistaken most of her cousins are on her mother's side. (But I might well be mistaken about that, don't quote me.) The only Jacoteys in her family I know of FOR CERTAIN are Jo, Michèle, Alizée, and Johann.
And I have very strong suspicions about one other person. But we won't go into that.