Basically:
- Tengu in the anime as the same VA as Sukiyaki
- Tengu is 78, which would be around the age Sukiyaki should have been if he lived
- Tengu is not featured at ALL in any flashback, unless he's Sukiyaki
- Somehow Oden had both Enma and Ame over 50 years ago. No details are given about how he came to possess these swords. Tengu is not shown, yet Kozaburo is, at least in Zoro's flashback. The reason Kozaburo isn't around during Oden's FB is because he's already gone. Yet Tengu....is just MIA
- He's a Kokeshi doll collector, as mentioned above. The Shogun castle has a room guarding the Poneglyphs.
- He's shown to have apparently known the Kozuki clan, as well as Yasue etc. He still says he's waiting for a certain man, and never elaborates on who this is. Very weird. He never specifies its Momo, Kin or Zoro.
- His face is still just hidden. Why?
There is probably more.
@Bounty has been a good pioneer of this theory, and I think it's legit tbh.