From all I saw so far, you would do best with a FR5 like MaEx still has. Which means OC ID FR5'd to OC, keeping OC Guard as own IFF. You can keep OC tech this way (given you limited it of some sort?! not sure here) and bring in other tech to compensate the inRP lack of accessibility to OC bases.
I have to agree with Reeves though, I miss a true OC faction (not just restricted to MR here, mind you). I know where your RP comes from and I saw lots of it during 72nd times. It's a very thin niche you try to fill here, I mean, sure go ahead. You create more activity than OCs NPC enemies. But at very least turn it into true revolutionary stuff, it feels really off to see you stage of OC bases.
In regards of GC, well, distrust is mild, isn't it? The one and only encounter I personally had with MR was literally "We would let any GC die, blockade Cardamine sales as a whole and we are allied with KNF!" - Make sure your faction members manage to represent this distrust then, will you? I'm gladly shooting you if that's what you want though.