Right click the user in AD > rename> enter new full name > press enter. Now the rename window will open. Change every field to the new name. Now open the users properties and change the email to the new email.
We add the old email as an alias, so under attributes there's a field called proxy addresses. Add the new email address with SMPT:youremail@address.com and the old email address as smtp:youremail@address.com.
The user will need to logout of their PC and back in before they see the name change.