its funny you mention this as I wanted to mention it too and you know what's crazier?...
If Kuina was alive right now, she would be exactly the same age as Tashigi!
Assuming her death wasn't faked and she is Kuina, what if Tashigi is a long lost twin?
They might be separated twin sisters, like Lola and Chiffon at least?
We don't know Tashigi's full name for some reason and Oda has kept her out of Wano for some reason, despite it being the PERFECT arc for her too! He won't let the Marines go to Wano yet, Orochi has been asking for Vegapunk too and who went to see Vegapunk a while ago? Tashigi and Smoker! There's still hopium as slim as it is lol.