If you could be a little more specific it would really help. Parks or resorts? Which ones? TS or CS?
Which seafood places are you thinking of?
The short answer is yes, some restaurants have outside seating with nice views. But not many of the TS ones do. The obvious one is Rose and Crown, but it's not seafood. La Cantina has water views, but is CS. The food court at POR has outside seating that overlooks the river.
Many restaurants have indoor seating with views of the water.