NO!
no
no
Safe - quite probably Tasty - probably not.
Most fish will remain safe to eat for up to six months. Fish that are fatty, such as salmon and tuna should keep for 2-3 months when frozen. Fish that are lean, such as cod and catfish will keep for up to 6 months when frozen. It would not be safe to eat fish that was frozen for 2 years because it would most likely be spoiled and could cause food poisoning.
Microbiologically, it would be safe. Palatability is another question.
It is only safe to eat if you want food poising
No!
Assuming it has remained constantly frozen for the three years hamburger is probably safe to eat. But, it may or may not taste good.
No it is not!
If it's a deep freeze and was OK when you put it in, it would be edible even after several years.
No!!!