Really enjoyed reading this post - thank you for it.
"Kevin, is that you?"
I have never heard of this strategy but it is very smart.
About your protocol to barricade in place (the bedroom) - have you considered home invasions during the day time when your MiL might not be in the bedroom? Is there a possibility that she might get cut-off from the bedroom and her firearm?
Regarding the sights at night: I don't suppose replacing the factory front sight with a tritium sight would help? Or would that be too blurry to be useful?
Great post! I hope you will keep us updated on how the laser grips work out.