There seems to be quite a bit of misconception and misinformation here. The ONLY thing someone can gather from an email, is your ip address. Not who you are or your address. The only one who has that info is your internet provider. And they will not divulge it unless there is a court subpoena alleging a crime or something. Not even to the police without a subpoena, unless there is an immediate bona fide life or death emergency.
Now if the same person emails someone from two different email accounts from the same physical location, the receiver can see they both came from the same ip address, even though they are different email accounts.