I know i'm a little late to the conversation but I think Discord is excellent for an Idea dump and presenting for review but for the assigning of tasks, it would be up to whoever is in charge to keep track of because things can definitely get muddled if not handled well. So for a wiki or a resource cache you could try Obsidian Portal if you want to do like Wiki articles and help folks keep track of correct source material and references. But for general collaboration, i think Discord is the way to go.