If you click the "Screen Options" tab in the top-right corner of the menu editor screen and enable the "Description" option, all the other Flex Menu options will appear for each menu item. You'll also want to enable "FlexMenu Elements", as that is what lets you add the Column Splitter, Widget Area, and Group menu items.
As for the menu icon, there seems to be a bug in the WP uploader that has issues with activating the icon feature; the latest
Vertex Upgrade Patch bypasses the uploader and allows you to just enter the URL of the image you want to use. There is a new version of the framework currently in development which should hopefully include an overhaul of the Flex Menu system, but I have no way of knowing when the new framework will be available for testing/release.