If the fact is these were "dead people" all along
Nope.
Those who survived the plane crash really survived. Those who died on the island really died. Those who took off in the plane at the end really took off in the plane.
The sideways world is imaginary time (actual term in Physics, by the way).
After actual death, the spirit or soul or consciousness enters this mental construct. Each dead soul imagines they had never crashed in the first place (never died). They imagine the kind of life they would have lived. Why? They are CLINGING. They will not accept death.
In a nanosecond (for some) or for a thousand years (for others) the imagined life goes on (or not). Each person must be "awakened" and "let go."
At that letting go point you meet with those other (now post-death) best friends and soul mate to make your journey together into the afterlife.
