An oversimplification: wikidata is a graph database where people edit semantic triples (subject, predicate, object) instead of text articles.
One could argue that the Fediverse is itself a graph database that anyone could edit, though current implementations are mostly focused on taking this abstract data and putting a usable shell that resembles specific applications.
Is every entry on a ibis an as:Article object? Could it be generalized for any type of Linked Data? This would make it possible to not only have a federated wikipedia but the whole wikidata project.
Why do you want to run an instance for that many people? Do you have 1000 people already, or is that just a number that you decided to work with? Why would people be interested in joining an instance with less functionality than the bigger ones?
Also: does it have to be Mastodon, or would you consider other alternatives? Pleroma and GoToSocial would be a lot easier to manage.
I’m downvoting because this community doesn’t feel like the right place for any type of meta-discussion.