There's a good chance that frozen whole crawfish will be rancid. The fat in the head/thorax part goes rancid really fast. Even when cooking yourself, peeling and immediately freezing tails, you have to make sure there is not a whole lot of fat on them because they will go rancid fast even in the freezer. Also, the couple of times we've tried the Asian crawfish products, we haven't been happy with them for various reasons, nor have a lot of other people from what I understand.
Regardless, there really isn't much to do with whole crawfish. You can make a bisque with the heads but I've only seen that done with freshly cooked.
My advice, thaw them out and make a small appetizer-type dish from them. That way, if they are bad, you'll still have dinner. Regardless though, you are stuck peeling the tails unless you want to give your diners the whole thing and let them peel and eat themselves. There's just not really anything else for a whole crawfish other then peel-n-eat.
