[Rainey222]

I know how to add custom home menu items (using smart playlists or library nodes). I'm able to separate my movies from the kids ones. So far so good. 
Question1: Is it possible to have widgets (like random movie or last added) with only using the specific node or playlist? How?

This is a problem area. The problem is these widgets and background art items and others all look to the library as a whole the pull their data. When you set up the node you have to add an extra filter for the path of the node data only to filter out the rest of the library, to every subitem in the node. Library node editor seems to have a glitch when you try to save that , and you may have to go in and edit it a couple of times.
I ended up editing the node files in a text editor and I've saved them for use in any install of Kodi so I don't have to repeat the process to set up my libraries.

You must make sure that you set up backgrounds on every menu and submenu so that the adult material don't show up in those menus from the random pull from the library.

One of the other ways to work around the issue is not to scan the adult material into the library so it's not available as background art unless the node points directly to the path and it goes and finds it for the node.

I will be watching to learn a better way if there is one.