In (1) under XREF category you will see all referenced files name.When you select the file name it will only list the layers in that file.Be sure to install the correct update for your software.
mac time not updating - Autocad xref layer color not updating
You might need to change layer properties for their drawings so it can fit your standard. Do you have to create a copy of the drawing, make necessary changes before you can use it as reference? Try to attach a file as XREF or external reference.
You will see layer properties manager will list the layers from referenced file as well.
The Layout ribbon tab is a contextual tab that is displayed when a layout is made active.
If you click on the Layout ribbon tab, you will see that it now includes a new Insert View tool.
By default layer properties manager will list all available layers. Whatever you do here, will not change the original layer properties.