"-san?"

[Being very British and very Victorian, he's not quite sure what that means, but he'll roll with it. That portrait, however, is crossing some god damn lines, and as soon as Chihiro isn't looking he's going to glare at it again and mouth "cut it out."]

I don't have a strong preference one way or another, but "JoJo-san" is just fine! I like the nickname quite a bit, actually.