Backup settings and favourites in Audition

Hasn't changed. You have to locate your existing Preferences folder (which almost certainly will be hidden if you haven't unhid it) and save everything in it. When you reinstall Audition you have to replace the vanilla folder that the installer will create with the one you saved. As far as I'm aware (I don't have one), the location in Macs is /Users/{username}/Library/Preferences/

There is a lot of stuff in there, and you almost certainly won't need all of it. Personally I think it would help if Adobe provided some sort of app that would save everything that people want to export in the way of settings, and then write it into a reinstalled version, but they haven't. The best that they've managed so far is for a new version to pick up settings from the previous one, which is fine as far as it goes - but not really far enough.