Balance them appropriate to normal fighters, more or less. Limit them to Civilian, Phantom, Generic, and maybe House Civilian guns as a counterweight to their several extra gun mounts (quantity over quality, basically). Give them 90% compatibility with Freelancer/Pirate ID, 100% with intelligence agencies and most pirates. Essentially, make them 'black market' fighters, as the implication was back in 4.84. Or even just generic civilian, though again, the gun limitation is probably needed for them to be balanced and still have some unique quirks.
Now, because "other servers might have Phantoms", there's a few workarounds needed (also, that's why I'm accounting for Phantom guns). First, make all the Phantom gear require neutral rep or better, and set the fighters to -1.00 like other ship purchases. Second, add a command - /temple, we'll call it for now. It functions like /conn, but sets you to the Temple of the Revenant, so you can buy the fighters.
With this setup, the Phantom fighters aren't wasting a ship slot here, and can still be exclusive elsewhere. It also makes a degree of sense in-RP; at least the Hackers and LSF (and probably others) have already attempted to replicate the fighters once, and I doubt any of them would be inclined to give up entirely.
Hell, I could even write up new infocards if it's possible to override them for this server.
Not that I expect any of this to happen; the title says "crazy idea" for a reason.
