I dare not imagine Momo and Hiyori's reaction.
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Despite her good intentions, Momo and Hiyori love their real father and still have all the tragic moments engraved in their heads. Then some creepy stranger girl comes around and proclaims that she is Oden and their "father".
How would you feel as a son/daughter of the real Oden?
I bet 99% would be massively irritated and furious at that person. Fully understandable btw.
If Oda really goes for another Momo-boob-gag with Yamato, once she reveals herself to him, I will give up.