If you disable ‘Mixdown,’ the Mixdown item disappears from the This Playlist… sub-menu of the playlist context menu … until you add items to the previously-empty Playlist, at which point Mixdown re-appears in the This Playlist… sub-menu.
If you disable ‘Options in playlist context menu,’ this also disables the (three) Options sub-menus in the Players (oops! ;)).
Incidentally, I think ‘Popup menus in folder browsers’ should read ‘Context menu in folder browsers,’ because that keeps it consistent with the two setting names below it. Oh: and the ‘Runtime features’ settings referring to ‘item properties and PFL dialog’ should read ‘item properties and PFL dialogs’ (two dialogs, hence plural and not singular :)).