My theory

My theory about Final Destination: Bloodlines is that the past main characters who had visions(Alex, Kimberly, Wendy, Nick, and Sam) are somehow connected to the survivors of the '60s accident.

Like, the survivors of the '60s accident might be their grandparents/parents or something. The same with bloodlines plot.

And that's why the new Final Destination is called Bloodlines—to give us answers about the past movies and how it all started.

Edit: I just saw an alternate ending of the FD3 that Kimberly and Officer Burke from FD2 was dead in a "bizzare accident". You can watch it here https://youtu.be/LaGXKa7802g