Oda can find a similar Yokai...who knows. But the fact Kaido can breathe fire....shoots flames in your argument. Oda gave a Seiryu an ability that it shouldnt have. Same way he gave a Vampire an ability that it shouldnt have. However that doesnt make Kaido any less of a Seiryu.....or Patrick a Vampire.
Or maybe those 2 fruits are actually a Special Paramecia and a Logia...and theirs no deep conspiracy theory.
Ryus have been breathing fire for decades in Japanese popular culture, it isn't surprising (Pokémon, Megami Tensei, RuneScape...). Indeed, he can give a vampire an ability it shouldn't have ("shouldn't", because as I said ryus breathing fire isn't Oda's thing), but the point here is that a vampire that sucks life-force happens to be what the monster bat of Japanese folklore is. It's not about denying that Redfield ate the vampire fruit but showing that, even for a non-canon character, Oda can't help but replace the creature's most characteristic trait (because the first thing it comes to our mind with vampires is drinking blood) with the less-known yet Japanese version of the myth.
But again, Redfield isn't canon and Marco has tons of Fenghuang traits plus the phoenix is actually merged as a creature in modern culture. As I said, when we see someone like Redfield in canon, then you will have a point.
Regarding Gaspard and Katakuri, sure, maybe those two fruits truly belong to their categories and that's it. But since they both work like Logias in every way and both are based on a manmade sweet, yet the only difference is that Katakuri's was retconned into Paramecia after being introduced as Logia... It does sound fishy.