I personally think that Falco will end up accidentally inheriting the beast titan and being Zeke’s downfall. I think amidst the chaos of current and future events, and the likeliness that everyone is being separated, the fact that Falco has been exposed to the spinal fluid will be forgotten. With Zeke’s likely escape and Falco likely coming to without knowledge of what happened, they’ll likely connect at some point and Falco will be positioned closely to Zeke. Zeke will scream at some point with Falco close by (could be when he tries to turn the military leaders), and Falco will turn mindless, eating the unsuspecting Zeke. There’s already some foreshadowing by Zeke of Falco being a “Miscalculation”, and with Falco’s family history and his recent sympathies towards Eldians, it might make sense.