The Villains Fanon Wiki has been adopted over a year ago by Tearface, who hasn't been active in more than a full year. I have 285 edits on that wiki and have been active for more than a year. However, when I tried adopting it, I couldn't. By any chance, what could you do about that scenario?
When I try to make changes to the page, a notice appears that someone else is editing the page, even though no one really is. The message will keep appearing if I keep clicking Publish. What's the problem with the page?
You had a stated intention of deleting the entire wiki; when you found you lacked the tools to do the deletions quickly you directed somebody else to delete all of the pages in a public post. Mass Page deletion and deleting the main page is quite a different matter from deleting a few spam or off-topic pages.
I'm sorry, but FANDOM does not close established wikis. You can certainly create a new one for yourself on the same topic, but you cannot delete the existing wiki in the process. Whoever wishes to stay on that wiki may do so.