Very cool stuff!
What do you mean sorry California? While there are some silly rules here, I still built a legal AR and I have other guns, so we are THAT oppressed.
Skill of the shooter (unless you are a professional) generally disappears under real stress. So for home defense, a shotgun is likely the best bet. Other than that you should just be very proficient with whatever you have. Personally, I keep a Glock 9mm with the same light setup in my nightstand. I also have a 1911, but it does not have a light mount so the Glock is the go to gun.