Lasers: Lasers have a downside in that they can give away your position. The upside is they assist aiming when your fine motor skills are deteriorated with adreniline. I got some early on but don't use them much. My daughters insisted on one for their P22 but don't use it now that they are comfortable with the P22. Crimson trace is the best I have used but I prefer front activation buttons as opposed to side activation like on the P220 model. Your finger easily comes off the button during recoil on the side versions. I would say you don't need one but can usually easily add one later if you decide otherwise (or have wife/daughter/grandma that demand one).
Home Defense: Yes we have a home defense plan including ADT, my dog that will pee on any intruder, a roll out ladder, safe positions, and strategic shooting locations. I try to plan what are safe shooting directions (including shots coming at you) so that anything doesn't go towards family. In most case I will be shooting in a downward position so I don't have to worry much about neighbors houses. Other things to worry about is not shooting the gas furnace, waterheater etc but they are secondary.
When/if the sh1t really hits the fan I can't really count on my kids doing what they are supposed to though. Identify the target. If a kid is running away with your stereo you can't use lethal force. If someone breaks into your house though many states allow lethal force because you can't read the mind of the bad guy to determine motive. He could be there for your TV, wife or both. :-(
I originally thought of Rock Salt for my shotgun but quickly decided that if a bad guy was in my house that lethal force was necessary to stop the threat. If he is high on PCP or some other drug bean bags, rock salt, or other nonlethal things will just make them mad. Petty theives beware, America is armed and you are the target once you step inside.