GMG is one of those NPC factions which has needed a good group of players for a while now. Good luck.
I'd like to add my ship suggestions... First, as others have suggested, ditch the Kusari fighters. There are plenty of good civilian ships which are more in-RP. Kusari weaponry seems fine to me, since the GMG did originate in Kusari.
Second, the Kusari Explorer seems like the perfect gunboat for you, so I'd also ditch the Kusari Gunboat. The Explorer has decent maneuverability and seven forward-firing turrets... Pretty good for a gunboat.
I'd also say don't bother with the Kusari Battleship(s)... They're giant flying hunks of junk, and I really don't see why you'd want them, even if there was good RP behind them. But I don't think the KNF would be handing out their flagships to a bunch of gas miners. And seriously, why would you want to fly that thing? I'd suggest using a Kusari or Zoner Cruiser/Destroyer as your flagship(s).