We shouldn't confuse killing an animal for research, and killing it for human food.

We don't embalm cows before eating them. Killing your seafood with ethanol, and therefore making it poisonous, would be extremely dumb.

They use a 1 to 3 percent strength ethanol solution. Also, when you say "poisonous" are you maybe thinking methanol? There's, uh, already pretty big business around getting people to ingest ethanol.

It does not matter. That procedure is a solution for a totally different type of problem. Keeping a sample of an animal in a jar in a museum for 20 years so you can do scientific research on it. The more toxic, the less attacked by bacteria or animals

Ethanol has one and only one purpose, and is critical. To avoid the body contracting while dying. This aspect is totally useless in the kitchen.