I run SFC 1 and spent ages replacing all the incorrect stock models with the correct SFB ones, then added in the missing races such as the Kzinti and Tholians.
Then came adding in the missing SFB ships in the lists such as the F-CL, F-CLS, K-E5, K-F4, various race Tugs and LTTs etc.
Basically, after many months of searching out models or making my own, adding to the shiplist, etc. I've managed to convert my SFC 1 V.1.03 to SFB Commander's Edition (Volume.III.) Rules, which is what SFC 1 was supposed to be.
I supposed that they left out the Kzinti just because even in SFB games they are quite a shock to fight against.
When something like a single SSCS can take out a complete warfleet from any other race in a single turn just by one 50+ high speed Drone salvo, if it deploys all fighters and PFs to help, I can see why they were missed out.
I don't have SFC 2 but I've heard moans that the SSCS was left out for the Mirak as well.
The general way, in SFC 1, to add in the other races is to "piggy back " them in with other races. For instance the Kzinti are in with the Lyrans, something that is ironic consideringthe rabid racial hatred between the feline races.
The Gorns host the Tholians, which because Tholian web generators and casters aren't in the weapons available in SFC 1, are fitted with the Disrupter or Photon upgrade options given in SFB.
Some weapons and devices have been added in from SFB that SFC 1 can support, such as Romulan Cloaked Decoys, Captor Mines and Kzinti Drone Captor Mines, all of which have to be pre-deployed in FMSE a scripted scenario.
As for FMSE, it bypasses the 64 ship limit of the stock SFC 1 selection list, which is great.
For the LAN campaigns we run here, it also means that upcoming battle scenarios can be scripted outside playing the game, set system maps can be kept on file and the deployment of defences, devices, ships and satelites determined by the players as in a real SFB table top game battle.
Well done Eagle Eye Software for FMSE, Ship List and whatever they devise next to support SFC.
To play any version of SFC to its full potential and for maximum fun / stress / panic, then playing in giant LAN games, that allow full squadrons for all 6 players, as opposed to the one ship per player limit for online games, is the way to play.
Human players are just so unpredictable when compared to AI.