I am able to research the first extra building slot again. In the order of research I got, Space Mines, Tactical Systems, First Extra Building Slot, Launch Facility, Sensor Improvements then General Improvements. As proof I already researched the first extra building slot, I have 5 buildings on the capital.
What counts as an attack card? I ask this since I got the pacifist achievement with one thorn and one enflame in my deck. Which I thought would mean I had two attack cards.
Lightkeeper triggers twice with hound (one for the first and one for the newly summoned one, even though that one doesn't summon anything). Also doesn't trigger on sculptor.