TL;DR jonathon (treasurer) was removed from the OpenCollective after they had a big argument with philm (project lead) over whether or not to authorize the purchase of a $2,000 laptop. After that jonathon posted his grievances on the Manjaro forum, to which philm responded by delisting the thread and removing jonathan as moderator of the forum.
And in addition to everything you listed, they appear to have hidden the thread the treasurer made and removed their mod abilities to keep the complaint from being seen.