In theory, can alcohol be used for anesthesia during surgery since its a depressant?

No: I understand this is just hypothetical, but it would not do well for a couple reasons. First, you v would have do drink enough to knock you out which would be unsafe. If you didn't, your inhibitions would be down and would want to fight the surgeon. It also can thin you're blood. The process of general anesthesia is very involved and includes a paralytic as well as sedation normally.

No no no: No way. Not even close to be an anesthesia drugs. To many complications associated.

Yes but poor choice: Alcohol intoxication can allow someone to tolerate a procedure but its a very poor anesthetic choice. For one, it would increase chance of aspiration where the contents of your stomach (etoh) would be regurgitated and end up in your lungs possibly causing a life threatening pneumonia.

Yes: Yes, in theory, but not in practice anymore since there are much better alternatives available.

Yes: Haha! yes, this might work. Although alcohol does not have pain relieving qualities so you would be asleep, but your body would still feel pain. You should try it and let us know!