DS would be a fun option, and from there I'd recommend either Morimoto or The Boathouse. We've had very good meals at both, most especially my favorite dish in DS--the buri bop at Morimoto. I'm generally not a fan of Signatures in parks as their quality rarely exceeds that of a middling restaurant. One of our worst Disney dining experiences occurred at Monsieur Paul, in fact. We did try Tiffin's and thought it quite good, and the bar area is nice, too, so that might be an exception. You're correct about AP being easy to get into--it's always been a hidden gem. However, as mentioned before, the hot rumor (which Disney has not dispelled) is that it is going to be a character meal for breakfast, lunch, and dinner. While I don't mind the first two meals being characters, I would bitterly disappointed if they take away Signature dining at WL. That's why I suggested it might be an option before it closes. And, you can watch the fireworks and have an after dinner drink from Geyser Point which sits right on the lake. They pipe in music there, as well. Have fun tweaking your plans!