If you want to make hype for Fifa 20, make us fight for those early packs in Fifa 19. I guarantee you that it would be as furious as TOTS promo. You included some cosmetic objectives but packs are all that matters. So make transition towards next season, no one cares about Fifa 19 cards anymore. I'd even play weekend league if it included really any kind of Fifa 20 packs.
Another thing maybe worth concidering is transfering of the small percentage (2-3%) of coins from Fifa 19 to 20.