Thank you, Flat!

Although it's been a while I did play "the two good Master of Orion games" but frankly I can't remember much of the experience. It would have been at the time the games were originally released which is a long time ago.

As to where derelicts would come from, shouldn't the death/elimination of any npc player (can't recall the appropriate term here) render its holdings derelict? It seems like that would generate them in an appropriately organic manner... Or am I missing something?

To me derelicts can be divided in 2 groups

Abandoned ships due to failure of engines or other systems due to some catastrophic event or combat and the other group would be derelicts ships from an ancient civilization that disappear eons ago and the ships are just abandoned in space, many of them still functional but just with a dead crew or without a crew. Or a crew in stasis.

Here are my quick thoughts on breaking down the idea to look at feasibility and gameplay.

First, what would cause a ship to become abandoned?
Just built and not bought yet. (only makes sense if ships are constructed in space by other ships with industrial construction modules)
Pilot/crew escape the ship for some reason. (requires separating ship object from AI object and logic)
Pilot/crew die because of ship damage to life support system or hull. (Could be from battle, or industrial accident. Anything less and they'd post a repair contract and stay with the ship)

What could be salvaged?
Cargo (I think Josh already demostrated this in a dev update video)
Data (picking up blue prints, assembly chips, sensor records, reverse engineering tech, etc)
Undamaged External Systems (dragging off things attached to its hardpoints)
Raw Materials (turn the ship like an asteroid)
Fuel (if game or mod uses a fuel mechanic)
Ship (repair on site, tow in to station, hire tow ship, sold by admiralty court)

How could it be salvaged in an interesting way without unbalancing gameplay
I think the only two things that could significantly affect balance would be reverse engineering tech and salvaging the whole ship at once. Balance could be controlled by limiting the amount that could be gained. For example, reverse engineering the tech of the ship could be limited to advancing the player on node along the procedural tech tree towards whatever was used to build the ship. Balancing the salvage whole ship could be handled different ways, some less feasible than others. If the repair/reactivating is on site, requiring large expenses and high tech would prevent a large jump from small ship to large. If towing in, setting tow size limits so that it would require a ship of similar size to tow (no little fighter towing a battleship) or be very expensive to hire a tow ship. Another idea would be similar to how salvage is handled here on Earth where the ship is sold and the salvager only gets a portion of the value of the ship. If there was a crewing system, you could require a large enough crew size to send over to a derelict as a prize crew.

What is feasible in Limit Theory?
I'm guessing that the mechanisms for salvaging cargo, data, external systems, and raw materials would be quite feasible to implement, be interesting, and add a new gameplay role of scavenging for AI and player.
Salvaging the whole ship in any of the ways could be very fun and challenging, and not all the options require other large system creations.
Reverse engineering could be important from a gameplay perspective because like in real life, if an enemy faction gets a hold of your wreckage, they can learn important things about you and better prepare to fight against you next time.

None of the above is a demand for salvaging features. Just my musings on what it could be like.