Hi,
floccus doesn’t do magic, but can only sync the folder structure that exists in the particular browser it is installed in. I suggest you have a look at the bookmarks structure in all your browsers. Some may have a bookmarks bar folder, others may not or have different folders. By default, floccus syncs the root folder, but you can also select specific folders to be synced. I suggest to select in each browser, a folder to match what you selected in other browsers.
missing some items on other browsers
These are likely browser-specific links like chrome://. The bookmarks app currently only supports http(s) and ftp links.