Crawfish are wonderful. But they are still crustaceans.
Oh. my. gawd. 
Just my two cents. IANAD. I used to be allergic to crab, but not any other crustaceans–lobster, shrimp, crayfish, etc. were all fine, but crab would give me hives. I never saw a doctor or got an Epi-pen, and now that I know a few people with serious allergies, I shudder to think of how I was gambling with anaphylactic shock. Anyway, one day I decided to try some crab after not eating it for about 10 years, and lo and behold, my allergy was gone. No reaction whatsoever.
No shell. ready to dip in sauce if you wanted to.
As far as farm raised or wild…this was the fresh fish section of a large supermarket. There were no signs of origin, and the clerk was just there to weigh out the purchase.( At least he wore rubber gloves.)
Crab, lobster, shrimp and crawfish are all crustaceans. Scallops, along with clams, oysters and mussels, are molluscs. They all live underwater (part- or fulltime) and are marketed together as “shellfish”, but they’re very different critters.