Should the merc ships for hire not be the ones that are already on the map?
Currently, it seems the pool is gerenated with a logic ditached from the fleet available to the minor faction and they arrive from a random hyperspace origin not from the planet of the minor faction home base
Hiring existing ships would make a lot of sense immersion wise but following needs to be thought of:
1. The available ships for hire need to be ships that are located in the home system (so they are not on a raiding mission) AND are not under attack by the player (AI attack happens right of the bat at the beginning of the turn so that is no issue)
2. Upon purchase, they head towards the nearest player planet or outpost from the home system of the minor faction
This would automatically take care of the supply balance: you can only buy what they were able to produce at the tech level they currently have and if you buy their ships, other factions cannot. This would put Phidi at a clear advantage when utilizing them as they have early access and more money so they can buy the best ships before others (once they actually start doing that).
They would also automatically avoid being raided (which is needed for them being military impaired) as they can leech off the Marauder fleets before the attack them
It would also mean the player would need to consider not just what to buy but also from who as the futher away the home system of the minor faction, the longer it is going to take for the merc ships to get here.
Thus especially on large maps, it becomes more important what the nearest minor faction to the conflict where support is needed has to offer even if it is not state-of-the art - merc ships that are ignored otherwise as they are clearly inferior
Also: Due to this, next time the player sees a Minor faction fleet, they can also think of: "Great, new ragtag merc ships for my fleet"