Day 1 Saturday
Check in CSR
Quick lunch at Pepper Market
Over to MGM
Need a suggestion for Dinner--
Catch Fantasmic
Be sure that, when you call to make an ADR for Mama Melrose's, you book a Fantasmic Dinner Package. If you just book the restaurant w/o booking the FDP, you will not be able to sit in the reserved sections at Fantasmic.
So, when you call, ask for a Fantasmic Dinner Package at Mama Melrose's for the date you need it.
The other 1-TS-credit option for a FDP is Hollywood & Vine, a buffet. We got tired of buffets last year & weren't too impressed w/ Hollywood & Vine, so we're trying Mama Melrose's this year.
Regarding the possible new character meal at Hollywood & Vine, I think that's going to be a breakfast, and I'm not sure if it would be an option for a FDP.
Day 2 Sunday
Chef Mickey Breakfast
Over to Magic Kingdom for the day
Light lunch, or snacks
Need dinner suggestion
On this day, if you don't want to use TS credits for dinner, a good counter service is Columbia Harbour House - the dining room upstairs is very nice, and the food was really good as well. Check out the menu to be sure there's something you & your family will eat; they serve chicken strips, fried fish, sandwiches, clam chowder, etc.
Many people like Pecos Bill's, but we've never tried it. Another good choice might be Pinocchio Village Haus - it has windows overlooking the "It's A Small World" ride. The menu looks really good too; we're trying this one for the first time this year.
If you do decide you want to use TS credits & pay out-of-pocket for another of your TS meals (like Chef Mickey's), I would suggest Liberty Tree Tavern (characters are Minnie, Goofy, Chip, Dale, & Pluto; food is American, served family style) or Crystal Palace (characters are Pooh & Friends; food is American, served buffet w/ lots of yummy selections - this was our very favorite buffet & our 2nd favorite restaurant!).
Day 3 Monday
Quick Light Breakfast in room
Over to Animal Kingdom
Pizzafarri for Lunch
Leave around 5:30 for dinner at O'hannas
Since you're already eating at 2 restaurants in the MK area (Chef Mickey's & WCC), you might think about switching your ADR from 'Ohana's to Boma at the AKL - for variety & also to experience another resort area. It would be a perfect ending to your Animal Kingdom day. There are exotic dishes on the buffet but American dishes as well. Plus, the AKL is gorgeous, and it's so fun walking around the lodge & looking at the animals. There's not any "fun stuff" at dinner like at 'Ohana's where there is hula hoop races, etc., but it's a very pretty restaurant & gets rave reviews! We really enjoyed it last year, & I wish I could fit it somewhere in our schedule this year!
Of course at 'Ohana, you do have the view of the castle from the restaurant!

Last year, though, even though we had an ADR, we had to wait for about 45 minutes for a table.
Day 4 Tuesday
Light Breakfast in room
Over to Magic Kingdom
Need a place with Chicken Fingers for lunch
Dinner at Whispering Canyon
If you don't eat at Columbia Harbour House on Sunday, you could eat there on this day. Columbia Harbour House has yummy chicken fingers, and, again, the dining room upstairs is so nice & relaxing!
Our 5th day in the Parks will be at Epcot
I'm not sure if this day is covered under the dining plan.
Suggestions for kid friendly places are welcomed
I think there's a restaurant that serves McDonald's in the World Showcase - maybe around Canada ??
Many of the World Showcase counter services have kid choices on their menus.
Last year, for our Counter-service in Epcot, we tried Seasons in the Land area of Future World. It was good (but crowded!), and the kids enjoyed their dirt cup puddings for dessert. However, this year, I wanted to try some of the World Showcase counters.
Regarding the Dining Plan, if you spend 4 nights, you'll have 1 TS credit, 1 CS credit, & 1 Snack Credit per person per night, and you can use the credits from the time of your check-in to midnight on the day of your check-out. So, basically, you will get 4 table-service meals (1 credit, not signature) & 4 counter meals over the length of your 4 night/5 day stay - w/o paying OOP for some meals.