In Amember 3 we could use email function codes to return affiliate id in a url and to input the member's first name, userid, password, etc. do those still work in aMember 4.
They're in a dropdown menu in the email editing interface - both in protect content > emails and in configuration > email and the links to edit different templates. Not all codes are available in all emails. In particular, the password can only be sent by the 'signup' email (on the configuration > email page) - unless you use this tweak: http://www.amember.com/docs/How_to_store_plain_text_passwords_for_users (I haven't tried that yet - it's on my 'probably going to need to do this later' list.)
We used to be able to use shortcodes when sending a newsletter type email to members. I cannot see that option in Amember4's WYSIWYG editor. I would like to address each member by first name and include their username. Other than Alex posting %user.user_id%, %user.login%, %user.email% where are the other codes for name etc.?
The drop down list only shows up when composing an email in plain text format. You can still use them in the HTML email format.