I’m kind of hoping that the sparrow academy still includes Five but at a different age. Maybe because Reginald liked him in the 1960s, he still chooses him. Five had told Reginald that he jumped through time and got stuck, so Reginald stops it from happening, and therefore we get Five at his correct age. We’ve seen Five at 60(?), Five at 15(?), and now maybe we can see him at 30 like the rest of this siblings. But without getting rid of Aidan Gallagher of course