I know this is more of a local issue, but I feel it rises to enough levels of offense for Staff to take action: a user named Madiyunu is behaving inappropriately on a wiki she founded: Matiyunu Wiki. Take a look at her response to the following thread: http://matiyunu.wikia.com/wiki/Thread:Madiyunu/@comment-CookieEaterTho-20171127073740 It is profane and offensive. Since you are a Staffer I think you have the ability to view it despite its deleted status.
Madiyunu behaves questionably all around her wiki, such as vandalism, offensive comments, and inappropriate behavior. Action should be taken.
You don't have to ask permission to create a wiki on a topic. It's totally fine to just do it!
It's good to search for an existing one of course. Since starting a wiki from scratch, especially on your own, is a lot of work.
If a previous Treasure Island wiki was closed, it might have been something that someone created and then abandoned. That happens quite a bit and those do eventually get closed by an automated process if nothing else ever happens on them.
I did a little searching and I could not find an existing wiki about the book.