I've a good feeling about the Wano Epilogue. Tashigi's connections to the Shimotsuki runs very deep. The fact she knows and holds a lot of reverence for the Wado Ichimonji is what also gives me those hopes. This isn't a simple (oh, I know that sword cuz I looked it up), she seems to understand the significance of the sword and chastised Zoro for wielding it.
And this wasn't because she just wanted to take a meito from him. She said nothing about taking the Sandai Kitetsu or Yubashiri, just the Wado Ichimonji.
Another thing about her is her etiquette. It's very Samurai-esque. She dutifully follows Smoker like a retainer would their lord, she despises humiliation and dishonor above all else, which is why she dislikes being spared after defeat, as that is the shame of a Samurai. From her perspective, Zoro was but a scoundrel who murders and lacks principles like a typical pirate. This would imply she was raised as such somewhere in the East Blue. And we know people from Wano migrated there. To me, that almost all but confirms her heritage is of Wano.