Hmm...since you're already doing a character experience on Wednesday with Toon Town Morning Madness, are you sure you want to do a character breakfast that same morning? I don't know if kids can OD on characters, but that seems like too much to me. Also, you don't want to have to rush breakfast because you're trying to get to TTMM.
The entrances to DL and DCA are only about 100 yards apart, so yeah, people go between the two all the time. Since DL always opens earlier than DCA and closes later, you might want to start your day at DL and then go over to DCA for a while, then you can pop back to DL later if you want to.
If you eat dinner early (5:30) lines at the counter service places aren't as bad. Places like Rancho del Zocalo and Plaza Inn have lots of seating, too. Generally eating a table service meal will take longer than a CS meal, so if you want to maximize park time I would eat some dinners at CS places...but with 4 kids under the age of 5 you might want that down time that you'll have sitting in a restaurant! If you want to eat table service meals I definitely recommend making PS rather than trying to walk up that day.
I prefer lunch at the Blue Bayou rather than dinner - and I'd recommend getting the earliest seating for lunch that you can so the restaurant will be a *little* less crowded and busy, at least when you sit down.
My favorite TS restaurant in the parks is The Vineyard Room at DCA, followed by the Trattoria at DCA. And I prefer Cafe Orleans to Blue Bayou. There's lots of restaurants at Downtown Disney, though - and all of those are just a short walk outside the parks.
You can see menus for all these places on AllEars.net:
http://allearsnet.com/dlr/din/menu/menus.htm
