I guess it can’t be done in this way. Since all posts must have their post owner while importing you can’t skip it completely.
I am not sure but I think few import scripts will import passwords too. Read Vanilla migration’s how-to topic.
Thanks for your reply. I studied the source code and I’m sure the vanilla mysql script does not import the passwords since it does not select the password column from the vanilla database.
I’m still seeking the answer for my questions, thanks for trying to help. 