@Zik:
With Zoro it just seems to be appearances.
He's not actually one and shows little to no interest in being one or his family.
The whole being enamored with samurai and one of the more popular ones to an extreme degree, wanting to be accepted by them are all clearly part of Yamato's story.
As for being an oni, don't see a conflict there. Don't see why he can't be both. Oni samurai.
Actually all of those things make it unique.
In all of OP no other character has all of those things in their design.
I think it's a bit deeper for Zoro. His instructor and childhood friend were both members of the Shimotsuki Clan and Oda has pretty heavily hinted that Zoro's own heritage is Wanoese.
Zoro's definition and pursuit of swordsmanship I think is also more closely tied to Wano than was previously apparent.
Over time, it seems Oda's association with Wano has only grown stronger as well. He's now carrying one of Oden's swords - Enma. He dueled Ryuma's zombie and returned Shusui (unwillingly), learned fire cutting from Kin'emon, and seems to be connected to Shimotsuki Ushimaru & Onimaru.
I'm not saying Yamato wouldn't continue to idolize Oden, but I anticipate part of her character arc will be setting aside the Oden costume and handing it off to Momo. With that being the case, I think the Oni / Ogre stuff isn't really an either or, but I think it's more closely tied to Yamato's core identity rather than someone she simply idolized and who inspired her rebellion.
If anything, I think her Oni / Ogre heritage is potentially the most interesting aspect of Yamato's backstory. We're still waiting to find out about that mysterious fourth group from whom Big Mom stole her Road Poneglyph and if the Ogres / Oni are somehow related to Oars / the Ancient Giants / Elbaf, then perhaps she would be as much if not more a representative of Elbaf than Wano.
I know it's unproven at this point, but the protectors of the Road Poneglyphs were seemingly some of Joyboy's closest allies, so I suspect we'll see a representative of each group as part of the Straw Hats. Jimbei for the Fishmen, Zoro for Wano, Carrot for the Minks, but the fourth group is a mystery. Maybe it's Yamato if there's an Elbaf connection somehow. I previously thought it might be Usopp given his close association with the giants. But Yamato might be a better fit depending on if any of this is accurate.