I'm not an expert. IANAL, either.
However...
Greg Porter made a decent reverse engineer of the formula for penetration. (It's in older printings of 3G3, and More Guns.)
I found the needed conversions... (Don: last week) all we need on that score is to collect the proof that all the stuff has been redone in 3g3.... makes the weapon list both a pain and yet very simple.
GCen can be reverse engineered from the Mongoose SRD.
DTons are in the SRD. As are all the major weapons, and most of the screens.
Ship components in the SRD: Bridge, Computer Model 1-9, Radar, Lidar, Densitometer, Jammers, Neural Activity Sensor, Staterooms, Low Passage Berths, Emergency low berths, Cargo Hold, Fuel Scoops, Fuel Processors, Luxuries, Ship’s Locker, Single Turret, Double Turret, Triple Turret, Pop-Up Turret, Fixed Mounting, Pulse Laser, Beam Laser, Particle Beam, Missile Rack, Sandcaster, Missile Bank, Particle Beam, Fusion Gun, Meson Gun, Nuclear Damper, Meson Screen, fission plant, Antimatter drives
The Crew Salaries also are in the SRD.
once the MGTHG comes out, it's going to be possible to do more.
Anything that's a formula is not protected by copyright, but instead by patent; I don't think MWM got patents for any of it. They will need to be presented in a different format, but anyone with 6th grade math should be able to accomplish that.
We clearly can not use: 3rd Imperium, Vilani, any proper names, the shattered imperium, Solomani, ship class names, world names & specific UWP's, maps, etc.
It's doable, since Marc didn't block the MGT SRD. I doubt he'll cooperate, tho', since it would compete with T5.