I agree that were some of the escorts can be hired should impact on their AI, and these 'limited escorts' should be much cheaper than the all-round henchbeing (see below).
Pirate cove-hired escorts should be pirates, trading escorts on the main stations, Tharg-hunting parties on military stations, etc.
In these cases, their contracting should have some rules:
- trader escorts are staple, and require the player to stay on the lanes (where others can also assist) and keep a clean criminal record or they refuse to accompany further, they could also run away after receiving moderate damage if outnumbered, or high damage on a balanced/winning fight;
- pirates stay together until so much profit has been amassed, or abandon the player if either the pickings are slim, or the damage too high;
- the military want a go on the Thargs, and could require the player to mis-jump at least once every three jumps or they leave, and attack the player if he commits an offence, but should fight hard and to the death;
- bounty hunters should be the same as the military except that they want to go to anarchies to hunt for pirates, or scoot if the earnings aren't enough.
However, I do like the idea of hiring simple henchbeings who'll follow around and do whatever you please

These could come from any poor systems, regarding only the economic level - be it a teeming hi-tech industrial slum with nigh-unbreathable air or a subsistence agriculture village lost in time, it's still a hellhole they want to leave...
The the government level could directly impact on the cost of hiring (corporates the most expensive), and inversely on the henchbeings' fidelity (tribal and feudal societies are the closest-knitted and most honour-bound, whereas to a capitalist, no money can pay for his own life).
The tech level should dictate the ship's quality and also influence the price - and here comes a tandem idea:
--->Should owning several ships, and moving the 'flag' to another ship ever comes, one could hire henchbeing pilots for a regular fee according to the experience to fly the excess ships and follow the player around.
The shipyard screens wouldn't need any alteration aside allowing the player to buy and sell a ship without losing the current one, in respect to building an active fleet - by swapping with the other ship's hired pilot, the player could upgrade or part exchange any of the owned ships.
You know those who, having been mugged and stabbed, fired, dog run over, house burned down, wife eloped with best friend, daughters becoming prostitutes and their countries invaded - still say that "all is well"?
I'm obviously not one of them.