No, because Cain inherited from his parents the knowledge of good and evil. That implies the knowledge of God as well as sin (so he was not completely "dead" as the Reformed believe). That makes him liable in his freedom to choose. Besides, the ignorance of the law does not make you innocent if you break it.
Wine is a DE-hydrant because of the alcohol
Not in small quantities to any significant extent. A wine that is 10-12% alcohol still contains between 90-88% water. Any sugar in the wine will also contribute to dehydration, but dehydration is significant only in large quantities.
The reason they drank wine over water was hygienic. One was sure that wine would not make you sick. The same could not be said of water. Besides, they didn't really guzzle wine the way we do. They sponged it by dipping dry and often hard pita bread into it to soften it and that alone prevented anyone from getting drunk or dehydrated on a cupful or two of wine (as the wine remained in the bread while it was slowly digested).
Total depravity does NOT mean that we are all born axe-murderers. :) It has nothing to do with that idea. It just means that because of the Fall, we are all born into sin and are slaves to it. Also, that we cannot choose God on our own. We cannot serve two masters. While our only nature is sinful we cannot come to God. God must deal with that sinful nature first. "Knowledge of good and evil" is a separate subject from the nature we are born with.
Before I was saved I had a knowledge that killing was evil, but that did not make me a murderer. Knowledge does not automatically lead to action. However, at that time I was still a lost sinner and doomed to hell because of my nature. Nature DOES automatically lead to action.
Thank you for the background on how wine was used.