So far, there have been many aliases/disguises/spies/secret identities that have been revealed throughout this arc.
We got a mere poor man Tonoyasu who is revealed to be Lord Yasuie, the former daimyo Hakumai.
The criminal Shutenmaru is revealed to be one of Oden’s Scabbards Ashura Doji.
Gyukimaru is actually Onimaru, a komagitsune who was once the companion of the late daimyo of Ringo, Shimotsuki Ushimaru.
The mysterious Kamazo the Manslayer is actually Killer of the Kid Pirates.
Komurasaki is actually Oden’s daughter Kozuki Hiyori.
Kyoshiro/Ushimitsu Kozo is revealed to be one of Oden’s Scabbards Denjiro.
Kanjuro is actually a Kurozumi Clan member.
X Drake has actually been an undercover Marine this whole time.
Scratchmen Apoo was actually working with Kaido’s crew prior to his alliance with Kid and Hawkins.
And I believe we are still not done with the reveals.
In my opinion Yamato being an Oden fanboy has more plotholes then Yamato actually be Oden according to the informations we have now.