Safekey and WebAdvisor are included in LiveSafe. Security Scan Plus is not needed at all as it is simply a sales tool designed to steer people NOT using the software to the McAfee website product pages.
It installs as an optional extra with 3rd party products such as Adobe Reader, or Flash or Shockwave players and therefore should be uninstalled manually - it will be listed in Programs and Features in Control Panel.
Always check when installing or updating such products that you deselect any optional extras such as that.
Thank you! Exactly what I wanted to know.