I am also allergic to crab (although I can eat other shellfish), my daughter simply doesn't like seafood, and my husband wanted no game meats. I had a menu with no crab on it, my daughter's "fish" course had no seafood - they put in substitutions that she loved, and my husband had no game. Note that there is also a full vegetarian menu available from which you can order. My husband swapped out a course for a vegetarian one, and it was delicious!
You can ask them to make a note of your preferences when you make your reservation. They will generally call a week or two before your reservation to ensure that they know your preferences, or you can call them and they'll note everything.
It is so worth it!