Ohana has grilled shrimp, along with a ton of meat so not exactly seafood focused. I didn't care for the grilled meats so much (kind of dried out), but we ate tons of grilled shrimp.
Not grilled, but we loved the shrimp and scallop dishes at Teppan Edo.
There are no crab legs available as a 1TS meal anyplace.
Trust me, I'd be all over that one if so.
Actually, unless things have changed recently there aren't any available as 2TS either...
The majority of your seafood options on DDP with 1TS meals are various preparations involving fish. There are a few places that carry shrimp of various types, like Ohana which the pp mentioned and a couple of the dinner buffets. The Cape May dinner buffet at the Beach Club has clams/mussels and shrimp too if I remember correctly - haven't eaten there for dinner in a good long while either. The Chefs de France has a scallop-and-shrimp dish that is quite good.