The pause menu also contains the settings.
The resolutions are set using a function in WBP_SettingsDisplay. This function first tries to use a default UE4 function to get the supported display resolutions, which sadly does not always work. For this case I added the most common resolutions in an array that will be returned instead.
Audio sliders are also in the known issues and fixed in 4.19.
You can upgrade your project to 4.19, but then you cannot downgrade back to 4.18. So make a backup first. If you moved the content files into your project, you have to replace them with the new 4.19 ones of course (otherwise you would not get the fixes 
). Simplest way would be to just repeat the integration. Also check the 4.19 changelog in the first post of this thread.