Sanji isn't a Lunarian, im convinced now
Oda is just baiting again like he did bymaking people think Sanji was going to fight King.
And i prefer that way. Lunarians have nothing compared to Sanji's flames. Magma is mere melted stone, not flames that emit lightning, that is on another level and we have nothing like this in One Piece, aside from current Sanji
I really can't see "Sanji being a Lunarian/half Lunarian" being a thing, and honestly, i don't think it would make any difference on his character arc anyway.
Unless Oda really wants to explain Sanji's power up, BUT this isn't something that we should expect from Oda, right? I mean, do you want a logical explanation for everything characters come up with? In One Piece?