Congrats on getting everyone on board with your trip!
Now, I don't have kids, so this might be the wrong perspective, but I would think it would be best to have a Character meal at the beginning to kind of kick off the magic of the vacation - then if you are only doing two, save the other for the end of the trip. This way its ending on another special note
Everything I've heard (mostly what's been discussed in this thread) has said that two discounts can NOT be combined. So you would have to see if the room discount or the free dining would be better for your family.
My guess would be that you need to get the whole package to get the free dining. but I honestly don't know. I'm sure one of the more experienced DISers will help you with that
Finally - for a date night dinner, I suggest Narcoossee's at the Grand Floridian. Its right on the water, so if you time it right you can see the fireworks from MK. Or, you can do what we did last May
We planned at 7:30ish dinner on a night with MK EMH until 2am! It was so fun to head back into the park later at night. We also got some GREAT photos from photopass since we were a little more dressed up.
Plus it might be fun for you and your husband to get to go wild and act like kids without the kids in tow