I don't have rebellion, I only have original sins right now because the gamestop app won't work on my pc. When is rebellion scheduled to be released?
June 12. If you got Rebellion now you would be using steam, not gamestop. Also there was a promotion that anyone who had any version of Sins got the $10 discount on Rebellion, if that's still going it might be your best chance to get it for a while. And you don't want to be modding original Sins, trust me.
Goa would know more about that...
Yeah. You can't spawn capitalships like frigates, as in they appear right next to the creator as with missile turrets, but you can have them warp into the planet like with returning armada. You must have the necessary fleet supply for it though. Capitalship slots are ignored currently in diplomacy but its now fixed in Rebellion (there is now an official ability that creates a capitalship).