If you're going to be in DTD anyway, T Rex might be a really great time for the kids-- but it's not really Disney special as others have said. I would maybe soak in the atmosphere at DTD-- see the
Lego statues, get food at Earl of Sandwich or Wolfgang Puck Express-- maybe even get a treat at Ghirardelli's or Goofy's (build your own!). For a first night there, with first night anticipation, there is so much to see and absorb at DTD I just don't think the meal is completely necessary unless your kids are dinosaur fanatics.
I also really love Sanaa-- my DH and I lived in Jackson Heights, Queens in NYC (which is the Indian neighborhood in NYC) and left our engagement trip STILL thinking it was probably the best meal we had on property. It was really the whole experience--the animals right outside (get an earlier reservation while it's still light out!) the bread with accompaniments, the wine flights, the appetizers, the DESSERT TRIO (best, most well-balanced dessert trio I've ever had) --- the entrees and salads we picked were also good, but I think it was really just the overall experience. The Indian food in NYC is objectively better Indian food, but you don't go to an Indian restaurant and get that kind of experience (e.g. ordering LOTS of naan with a huge variety of dipping sauces, a variety of things portioned smaller so you can have two things plus rice, desserts, wines). It was very unique and the animals were so awesome to watch.
Only you will know which restaurants will fit into your schedule the best, but considering the mixed reviews I've seen lately re: the antics at 50PTC, and given the mediocre reviews I've seen of Boatwrights (LOVE Port Orleans Riverside, but if you're not staying at POR or POFQ I don't know if the trip is worth it), I would keep Sanaa in the running if you can.