In this context, by realistic I mean that the red thrusers in the following image should provide 0 net thrust to the structure they are attached to

Direct IMGUR Link
These guys can explain the ideas behind a warp drive better than I can:
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015936.pdf
And BAE Systems has some thoughts on “shields”:
https://www.baesystems.com/en-us/article/directed-energy-atmospheric-lens-could-revolutionise-future-battlefields
(Admittedly this isn’t exactly the system portrayed in Empyrion, but I imagine Empyrion’s method is probably much less performance intensive.)
As for “Fusion Cells” since what they actually do is fill a fuel tank, I would argue they should actually be named “Fusion Fuel Cell” or perhaps, with reference to how they actually apply to game mechanics, “Tier 3 Fuel Cell”.
As for the gravity generator. that is likely to be pure fiction. However, would you prefer to not have the option when moving around in a CV or space station in game? There are, however, some interesting initial rumblings: https://www.sciencealert.com/a-mathematician-has-proposed-a-way-to-create-and-manipulate-gravitational-fields
IMO, a cargo box/module should have a volume defined by it’s supposed in-game size (2 cubic meters for large blocks, .5 cubic meters for small). Second, each material already has a mass per volume, so it is simple math from there. Admittedly; cargo containers, the players backpack, etc are all TARDISey. But then they have to be not to be annoying.
As for power generation and consumption, since I know of no reference to turn an Empyrion “Power Unit” in to something more familiar like Watts or Joules, I can’t really comment. I imagine that’s why they chose to use a fictional unit.
we did, long before we entered the escape pod, or, in HWS’s case, long before we were cloned. It was long, tedious and boring. We should be glad we can be cloned with our memories intact. otherwise the survival start would be much slower and more boring than it already is.
Nanites.
This is a video game based on some made up stuff, which is largely in the game to remove annoyance and/or add game play, and also based on some fairly realistic stuff. It seems we have a difference of opinion on which parts of the game should be governed by which concern.
To make an argument in favor of “exposed” thrusters (note that personally, I think only that their intake and exhaust points should need to not be blocked, there is no logical reason to require the entire thruster to be outside the hull): I think it would add greatly to the games PVP to be able to disable a ship by destroying/damaging it’s thrusters and turrets, then when it is disabled, to be able to dock with and board the ship in an attempt to seize control of it. Do you disagree?