No dining plan on discounted rooms. You have to purchase a package which includes full price on room and tickets for all.
Keep in mind that MIL can get the CM discount on meals (20%), but CMs can not get their discount at dinner time anymore until after 8:30PM (which is stinky). So if you want a discount and WANT to dine with MIL make sure you do late lunches.
Have MIL check to see if HDDR is still 50% off for the 9:30 show, that might be something you may be interested in. Also, the American Cafe at the WWS was runing a 50% CM discount too--of course before 4:00PM (blacked for dinner). Keep in mind that when getting the CM discount on meals, the CM MUST be dining with you.