show recent apps icon in the blog sample three by three buttons floating menu

Try using these properties to set a path:

BTTMenuItemIconType = 3
BTTMenuItemIconPresetPath

What might be easier:

Starting with 4.746 you can dynamically load items into a floating menu using java script. This is not yet documented but the same scripts as for "Show Context Menu (New)" and "Choose From List" will work.

(additional supports property templateItemUUID to use an existing floating menu item as template)