Still absolutely convinced Kaido is Harald's illegitimate son in the same way Franky is to Queen lol. Maybe after God Valley that gets addressed XD
Linlin im not sure because her parents look normal at least lol. Shes deemed a freak of nature.
100%, Kaido is Harald's kid. Kaido is being teased oddly in this flashback; him talking to Linlin about his Fruit is interesting. Oda is clearly waiting to show up Kaido getting his Fruit for a reason.
I think Kaido's mother was either on a Sky Island, and Harald couldn't find the Island again because it drifted, or was a Buccaneer on a secluded island, and Harald never returned so the Buccaneers wouldn't be discovered.
I think it's a Sky Island, though: we've seen Loki drop off the Sun World into the Underworld Twice (once via Estrid, the second time via himself), Harald jump off THE RED LINE, and Hajrudin nearly fall to his death when he went to stop Luffy from releasing Loki.
The entire family is obsessed with Sky Diving, and Kaido's introduce jumping off a Sky Island: Elbaph is full of Sky Islands: Onigashima became a Sky Island via Kaido's Flame Clouds briefly.
I think Kaido ended up in Vodka Kingdom, by leaping off a Sky Island.
I think Linlin was latent Buccaneer Genetics from both Parents' Lineage Factor coming together to create a child against the odds.