Toddlers... Most difficult thing ever!

This is EXACTLY why I never have a high chair in any of my sim's home. What I do with toddlers is I will have someone fix a serving of whatever, and let them put it down where ever. Then I will direct the toddler to go over and take a plate. They will then go find themselves a chair to sit down and eat their meal, and they won't throw it on the floor that way. The reason I mentioned servings is that later on after the toddler wakes up, I will take the leftovers out of the refrigerator, and again direct the toddler to take a plate. If their bedroom is to far away, I will just place the serving platter in their bedroom, and have them grab a plate there.

Now as far as breaking the dollhouse, just lock the door to not allow the toddler in their older siblings room, assuming they have their own bedrooms.