[Fingers]

Have you tried different map sizes yet? Sometimes you can hit various limits easier on a larger map, while a small map works just fine.

Creating a ton of fleets will require you to modify the world_max_fleet number in numbers.ini. Trying to create more fleets than this shouldn't actually crash (just cancel the quest), but it might be worth a try. If your fleets are large, increase world_max_ship as well. Doubling them should be plenty.

You should remove the PLNT lines from your offmap fleets as you're not creating a new planet.

Also, a ton of attacking fleets may "hang" for a long time as they all try to find a path to the target planet. This is why the Ravian invasion fleets are set up to start at different times. If the fleet is slow-moving (no nebula drives) it gets worse, as the pathfinding algorithm has to actually simulate the fleet traveling through space to make travel time estimates and avoid black holes etc.

I'm going to play the mod on PC a few times today.. is the download current?