Thank you so much for this post. I feel like you really get it. Yes, MIL and DHs criticism was the same- usually that I wasn't organized enough. I think my disorganization bothered DH, but she was there highlighting it and emphasizing it all the time. I felt like I tried harder and harder to please both of them, but I never, ever measured up.
I am now undergoing treatment for ADHD to learn better organizational skills because I am slightly disorganized. But I do feel it was exaggerated etc.
Here's the thing though. MIL criticizes every woman in the family. For instance, her SIL (DH's aunt) is too organized. MIL makes fun of her OCD. So, I really should take whatever she says with a grain of salt.
As for narcissistic tendencies. I don't know if she has npd etc. I do know she can't stand not getting her way especially with her family and will go to extreme lengths to ensure compliance with her demands- guilt trips, pitting family members against each other, screaming and hanging up the phone, having meltdowns on holidays (my first mother's day 2 months after I gave birth to my eldest) involved a screaming fit between her and DH's brother at a fancy restaurant). It was a lot. A LOT.