Oda has three explicit female partners for each of the big three male Straw hats waiting, should he or the people at ShΕnen Jump be interested in portraying them having kids in the Epilogue and setting up the sequel series. Sanji with Pudding, Luffy with Hancock, and Zoro with Hiyori. That doesn't mean these three in particular will wind up as future Straw hats wives, but I think the people at the top likely told Oda to at least leave the door open for a sequel down the line once he finished One Piece in twenty years or so. Personally, I would be okay with Hiyori being Zoros wife. Seems fitting that he would settle down with Wano royalty after he beats Mihawk down the line.
And just to be clear, Two Piece or whatever the hell it will be called is all but assured. Better get ready for Buffys adventure!