It is also, sadly, incomplete.
If it were complete, what would I need you guys for. I'd retire on the island of Switzerland in the year 2890
if it's a new timeline wouldn't that just change Future X to being Future C or wherever other letter as it would be separate and independent from Future X?
I'm not really prescribed to the parallel timelines concept, the self-consistency conjecture which spawned it and many worlds interpretation just seem to be really grasping. While it's equal conjecture, they both seem too 'sci-fi' - just like black holes being infinitely dense (disproven via hawking radiation). Life has taught me consistent stable answers are straight forward.
What I'm suggesting is past & future exist on the same plane as eachother and cause the present. Its just perception of both that equal now.
The basic example of observing the past would be light from distant galaxies/stars. That information is the star billions of years ago, you're looking at the past. It's that well known concept that physicists kind of adore to rewind to, and which sparks these conversations. If you shift your perspective as the observer right now to be sitting in Andromeda looking at earth in the milky way through a giant 'magic' telescope, you would see the billion year old earths light, and effectively be looking at our little blue marble a billion years ago. That's the conservation of information at play. Change the distance and you change the time observed on earth. So let's not go so far away, 10 Light years, zoom into Montoyas house and we can see TEST being formed. Or what you were doing 10years ago.
So really the information for the past exists, it's just really far away.
Data existing but being unaccessible is much less of a problem than you'd think. At least I think you think I think.
That's where quantum entanglement becomes a subject to provide the production of the past. If that photon was entangled, and its pair happened to be 'trapped' on earth - we would have effectively a quantum data recording.
Superficially entangle the sequence, and maintain order somehow, even for 5minutes. Those particles/waves wouldnt just represent 5minutes ago, they would from our perspective/perception, be 5minutes ago.
It's aligns with special relativities concept of time being relative to the observers frame of reference.
I guess we could explore the other 3 points, they all have equal answers I suspect. Much like as it was mentioned, 'if you know everything you can know the future'. Maybe an answer a little less complicated than the ultimate equation to life.