Ok, this may sound dumb, but I'd like to discuss the Fall of Guardia. The only ACTUAL proof that it happened is that anime FMV right? Well, here's the problem.
In the PSX version of Trigger, you only get that FMV if you beat Lavos while CRONO IS DEAD. Maybe this implies that Guardia would have fallen if Crono would have died, but maybe there was no Fall of Guardia when Crono became king when he married Marle.
I hope you understand my reasoning. Did the Fall of Guardia actually happen, or was that cutscene just an example of what would have happened if Crono wouldn't have made it?