Hm, but you said: Fanlore naming conventions say: "Articles about individual fanworks should include only the work's title in the page name".

I understand that as: someone creates a page about a fanfic titled "The Awesome Story" and names it The_Awesome_Story. My suggestion would be to name it The_Awesome_Story_(fanfic) from the beginning, no matter, if there is already The_Awesome_Story_(podfic) out there or not. A disambiguation page can be done later, if there are both pages. But that has no impact on the naming of the page.

I don't know, how that would work with the search though. If someone searches by title, they wouldn't find the page, but a search result where the page is listed. Unless there is a disambiguation page called The_Awesome_Fanfic right from the beginning, even though only one link is on it (in which case it would be a forward, I guess? Hurm.