Ever since we installed 1.2.2 we've had these issues. As you wrote it's two to three different scenarios.
1. Everyone crash, including the server.
2. Everyone except the host crash, server is rejoinable
3. A single client crash, other clients and server can continue.
10-30min until it happens.
We've played alot with 5-15 players. We noticed this issue immediatly after we patched to 1.2.2 . hard to say if it's related to FC3 or if it crash with A-10C and BS.
Edit: And we only use vanilla software, no mods what so ever.