firstboot prevent to create user without a password, without any message! i suggest to remove restriction to have account without password. because all remove interact impossible with account without password (sshd for example)
Thanks for the bug report. The next build of firstboot will display an error message in the case where the user doesn't enter a password. However, I will not allow creating a user without a password. The user you're creating here is intended to be the primary interactive user on the system and really ought to have a password.