In the new movie, why were both Vegeta and Goku unaware of Broly. They didn't recognise him even though Goku/Vegeta had fought Broly a long time ago. Feel free to add/edit information.
They didnt recognize him because the former Broly movies were non-canon (not written by Akira Toriyama but by Toei animation) so they dont follow exactly the same timeline-continuity. In the new Broly movie story, Goku and Vegeta never met Broly before, the events of the 3 former movies never happened. Besides this Broly is supposed to have a different personality than the former Broly, who was pure evil who wanted to destroy everything and this is somehow a good guy.