Both are loud, so if this is an issue for either of your little ones, then they won't work but my choices are:
Chef Mickey's - we always do a LATE seating and basically make brunch out of it - go to MK for rope drop, then hop on the monorail for 11:00 ADR at Chef Mickey's - we've done this a few times and NEVER had an issue with the food being cold, etc. It's not nearly as crowded as other times so the characters are able to spend much more time with the kids.
The other one is Playhouse Dine at H&V if your older one is into JoJo and the Little Einsteins. They have the kids get up and dance - it's lots of fun, but again - loud. For this one, I would try to snag the earliest lunch ADR (which from what I recall is around 11:30-ish??) - before it gets too crowded and added bonus, there's breakfast and lunch food out.
I have no girls, so can't comment on anything princess-ey, but the Princess meals seem to be the most popular with the tiara-wearing crowd around here!
Have fun whatever you decide!