Well, the Rebels have mainly used diplomacy in this game, so I'm not too worried about attacks - especially not in the Sluis sector, where they've had absolutely no presence, so I was able to simply send out a couple diplomats and win the entire sector over with a single fleet and a couple Carrack-class light cruisers. Sabotage is also not an issue. Luke Skywalker is being sequestered safely away on the Outer Rim, on a single Strike Cruiser that jumps from place to place and doubles as an exploration ship. I do that with all my prisoners in case they escape, this way all they get is the location of one Strike Cruiser, and the fact that it's way off on the Rim. Han Solo managed to escape from Endor, but Luke's been imprisoned for over a thousand days - maybe even 1500 - and I've kept him mobile on the Rim to keep him from being freed.