Yes.
No..yours are probably just rotten
Yes, but if you store canned anchovies properly in a cool and dry environment, they will last a long time. Check the expiration date or "sell by" date for more guidance on how long yours will last.
Yes, any canned food is fully cooked, it's part of the canning process.
If you are referring to the canned product - yes, it is pre-cooked. .
Anchovies may not be quite as tasty after the expiration date but being packed in oil, canned and salted you aren't in any danger from food poisoning if they are only a month past.
no
Not usually, but it should be heated. You can just put it in a saucepan on a medium heat until it gets to your desired temperature. Unless it specifies on the label, you most likely will not need to cook canned pork and beans.
Lettuce
You can eat them as they are since they are already cooked or you can heat them up.
cooked from frozen: 180 gr cooked from fresh: 180 cooked from canned: 242 according to my medifast sheet
Canned vegetables aren't the best for diabetes, I'd suggest if you have diabetes eat raw or cooked vegetables. Canned vegetables are good, but they don't taste as good to me.