Why not set in the same universe as the 2018 Mortal Engines movie, but set thousands of years after its events? Mortal Engines takes place 1000 years after the present time, and this mod takes place 10,000 years after the film.
Okay, Bryan, I am going to try and explain this to you in very simple terms.
The reason why this is a bad and terrible idea is because you are trying to deceive people. You say "This game takes place in the Mortal Engines universe!" in the hope that people who liked that universe are going to be interested in checking out your work.
But what happens if they do? They see that you lied to them. Because, by setting it "10000 years in the future", it is no longer the Mortal Engines universe. There is nothing
that connects what you actually did with what you claimed to have done.
So now, not only do you have a bad and terrible game (because, Bryan, you do not have the skills to make a good
game yet), you have also pissed off the people who would, presumably, be the most interested in what you had to say.
Do you wish to have a reputation as a liar, Bryan? Do you want to be seen as someone who makes promises with no intention of ever keeping them? Because this is how you get that reputation.
As with Portal and Portal 2, why not relegate any Mortal Engines-related references into a tech room database?
What's the point of doing that? When Valve decided to connect Portal and HL2, that was a neat little easter egg, something they could do at that point because, unlike you, Valve had a large and hungry fanbase that they could please that way without much effort on Valve's part. Portal, as a game, had to stand on its own merits first and foremost, and it did. In other words: The Portal games were successes largely on their own merits. They were not advertised as "A new game series in the Half-Life universe".
You, on the other hand, are putting the Mortal Engines connection front and center. You are coming right out and say "This game connects to Mortal Engines". This goes back to the point I made above: If you do that, you will disappoint people because they will think you lied to them. If that's what you want to do, fine, go on and lie as much as you want.
But do not expect to be welcome here or anywhere else if you do.