[Suicide Junkie]

Those can be modded to be ship only, rather than "Ship/Base" as they currently are.

Solar sails are useless if the ship has zero standard movement.
On fighters, solar sails will provide movement even with out engines, but SE4 has a quirk with ships that if they have no engines, sails don't help.

Emergency propulsion could be modded to be an engine with a "pulse" mode, whereby you get a burst of speed, then travel slower until it is repaired. In this way, the base would not be allowed to have E.P., since they count as engines.