The Ghost story does not exist in the script. In the script the thing that makes the drone crash and makes the combine harvester's act up in the beginning of the film is a small metallic orb machine thing that crashes to earth from a black hole that is newly discovered near Saturn (had not been hanging out there for 50 years or anything). In the process of chasing down the drone they discover the orb. Cooper tries to pull the data off of it but can't make much sense of it, and leaves it in his barn. yada yada the orb is what leads them to finding the hidden Nasa base. Later on when they are going through the blackhole thing/exiting spacetime as we know it they discover this device which controls gravity (the thing that michael caine's character was "trying" to figure out the entire film). Also there is no plan A plan B thing in the script btw. They realize this device can save earth and i'm just going to assume is Matt Damon's character (or could of been any of the others, there were only the handful of humans that went on the trip) and Cooper decide to take it back to earth, and they program the device with all the information they've gathered about singularities/blackholes/gravity/etc, give it the coordinates to nasa on earth, and then start to fly off to take it back to earth. Then cooper remembers this thing falling out of the sky and realizes that they don't survive the trip back, only the device does, because it can control gravity and survive the trip. He bails, and matt damon's dude and his ship and everything else dies. The device makes it though, and sets off the chain of events that make the events of the film happen. It's not cooper's daughter that unlocks the mystery of the device and saves mankind, it's like his grandson or great grandson or something. Earth has a slightly longer time table than presented in the film.
Cooper isn't an astronaut, he's just a pilot and engineer. He doesn't know anyone at nasa and I forget now, but somehow he talks his way onto the mission.
The robots (tardis, etc) are more like ironmen drones than weird rectangle things. They were the only things sent through the wormhole initially, that whole 12 scientists sent to 12 solar systems through this 1 wormhole thing didn't happen. In fact there is only 1 planet on the other side of the wormhole, and it is orbiting a super massive black hole and about to be ripped a part. That planet doesn't have waves, it's actually the ice planet matt damon was chilling on from the film. However, unlike in the film, the ice was just cloud layers, and underneath the ice there was an actual surface that had this weird fractal hivemind lifeform living on it.
The robots sent through that made it there were Chinese military robots. They were sent to find a habitable world and set up a base camp, and figure out a way to save the human race. but after they were sent the "war" broke out and the starvation/famine hit earth/etc/etc and china, like the united states, no longer exists as powers/countries.
The surprise conflict in act 2 which in the film is matt damon going crazy, is in the script, Tardis (or actually, one of the chinese drones disguised as tardis) going crazy. Which leads to them going through the black hole which leads to them exiting reality/spacetime as we know it, discovering the rest of the chinese robots who cus of #relativity have been working on a way to save mankind (as they were programmed to do) for like 50k earth years, and they were the ones that created the gravity device.
There actually were interdimensional extra planar beings that could only interact with our universe via gravity. They saw the life on that ice planet was about to die and they created the wormhole so that man could travel there and save that life form from extinction, not the other way around #dundundun.
Cooper had collected some of the fractal creatures and after the whole ordeal with black holes and extra space/time travel he eventually makes his way via spaceship back to earth. But it's several hundred years later, He arrives and there is no life on it whatsoever, completely barren frozen wasteland. He assumes all humanity is lost and sits down and prepares to die as massive frozen winds are about to tear him/his spaceship etc apart when he drops the vials of the fractal creatures which immediately begin to thrive in the frozen wastes of earth, and he is saved by another spaceship from "Cooper" station.
He meets with his grandson/great grandson whatever it was who is super old and stuff much like it was his daughter in the film. He does go off and look for brand, who had decided to explore the cosmos or some shit through the place outside of existence that has nothing but wormholes to every where or some such shit. The film reason for her continuing on (that cooper sacrifices himself so she can finish the mission, and she does go to colonize that planet) was better than the script in this instance.