Title says it all. I am about 90 weeks into a sandbox game and still only have Leia, Mon, and C3PO for heros. How do I unlock more as none of my planets have any options to build them, is there something I am missing? Empire has dozens of heros already and some insane fleets on the hardest difficulty. I also have control of most of the core worlds already including Kuat, Coruscant, and Corellia. Is it possible to get NR tech on sandbox or am I out of luck?

Appreciate the help, first time playing the mod and having a blast, just need to understand what I am doing wrong here.