Well, it's official! I may end up incarcerated or institutionalized before we get to Disney. My aforementioned DMIL had her FastPass window open this morning and since she couldn't add herself to our FEA reservation, she cancelled the one we had made, and made another at the same time we have dinner booked in a totally different park. To top it all off, since she couldn't change our 4yo DS FastPass, we then had a Fast Pass for him alone and another for the rest of us hours later.
My wife is about to take away my car keys...