With Flair a free man now is there anything stopping AEW doing a Horsemen reunion (copyrights and the like?).
You could have Flair, Arn, Tully and Malenko be interviewed in the ring by Tony. The Rhodes' come down to make nice with Flair, Sting comes down to do likewise, and then The Pinnacle spoil things by storming the ring and jumping everybody (save for Tully, who
was in on the thing the whole time). That way, you get the reunion on Dynamite, and the setup for some fresh feuds (MJF/Wardlow vs Darby/Sting, FTR with Tully vs The Rhodes Brothers with Arn).
WWE 100% guaranteed owns the Four Horsemen trademark and everything associated with it, and I'm betting that's why they got put into the Hall of Fame as a unit, so that legally WWE could demonstrate continued usage of the trademarks.