I have a 2.5yo and 1yo. My oldest is younger than yours but maybe this will still be helpful. We recently went and it was my 2.5yo's 2nd WDW trip and she has also been to
Disneyland. It was our 1yo's first trip.
Right now we mostly do character dining for ADRs with our kids.
-Crystal Palace early lunch (11:30) - I think the Pooh characters are always so great with the little kids. My DD adores Pooh & the gang so it is a winner for us. The little character parade is fun and actually the food was decent when we went a couple weeks ago! I was pleasantly surprised. Hadn't been there in years.
-Akershus or CRT - I actually prefer the Akershus princess experience as a whole but your 4yo might be enamored with eating in the castle at CRT! I think everyone needs to do CRT at some point, but I like Akershus more. DD LOVED the little princess parade at Akershus - Cinderella grabbed her hand and led the parade with her and she thought it was the coolest thing. We did CRT on DD's first trip and Akershus on the 2nd. We plan to do Akershus again on our next trip (she'll be 3) then CRT again when she's 4.5ish. Note: we did an 11am lunch at Akershus which was actually the last breakfast seating! This was awesome for my kids because they like eggs/potatoes/bacon/fruit better than what would have been offered there for lunch. Worth noting since many of the places switch to lunch food at 11, but not Akershus. They switch at noon. We don't like to do TS early in the morning so it was a huge perk to get breakfast food at what we consider WDW lunch time!
-BOG lunch is a great idea because it'll be quicker than a sit down dinner and you'll still get to enjoy the atmosphere. Since we mostly like character TS now, we like the QS lunch option, although you don't get to see the Beast (my DD does not care about the Beast unless Belle is in the vicinity, and if we met him I think she would just ask where Belle is
)
-We were supposed to eat at San Angel Inn this time before Irma cut our trip short. We rode the Gran Fiesta Tour ride in Mexico and DD kept saying "I want to eat there!" and pointing at the tables as we floated by. We didn't get to use our ADR because we had to hit the road early, but I think it's great for kids because it's loud. We are there many times pre-kids. Downside is that tables are close together and it's dark, but it's such a neat atmosphere. I thought my DD would have liked eating there and she pointed it out to me, not knowing we were supposed to. I was right!
I don't love anything that has the classic characters unfortunately. We have had the most amazing classic character interactions at H&V dinner, but the food is awful IMO. Chef Mickey's is so fun - seeing the monorail go through is fun for the kids, but again I don't love the food.
Times like these I really miss the Liberty Tree character meal. It was my family's go-to growing up and I wish I could share it with my kids. We had so many memorable experiences there.
Have an awesome trip!!