But if this is related to Kashin Koji, the question would be how?
Like why would Amado get this DNA specifically?
Maybe he found Jiraiya's body and wanted to reconstruct it to be his android so that he could defeat Jigen.
But the question would be when did he retrieve the body, how did he do it, and why just Jiraiya?
I have no idea. Plenty of other people died that Amado could have taken. Unless the reason Jiraiya was not able to be found was that he went down a riverstream and into another place. We know that Amado had to read up on the Fire Country and whatnot, so that could explain why they're not exactly familiar with the place, and Koji then relayed the information he remembered from Jiraiya, so that could explain why they seem like they know things about Konoha.
I'm sure there are more factors, but this is just a theory... a game theory.