looks like these views are created from Cloned Folders. i think that's why icon of the top tree is the same as a Saved Plan icon & not a folder...
you can't delete views in cloned folders because these are associated to your Stories. you'll have to delete the story if you want to delete the saved view -- however, deleting stories will also delete all the other views in Cloned Folders like the Design Development Plan. i doubt you'd want to go this route. my suggestion is to simply rename the saved view to "--" or something similar.
XREF-ing still exists, but rarely does anyone do that these days & i personally don't advice it. only because it brings in Attributes from the external file, most, if not all, are unwanted. such as new linetypes, new fill types, new layers etc., all with names which are completely different to what your attributes are set up in the AC file.
if you want to reference a view from one AC file into another, you can bring it in as an external drawing. from the image you attached, it looked like you wanted to bring in the RCP from another AC file. in that other file, if it isn't already done, save the view & place it as a Drawing in a Layout. copy that RCP Drawing & place it in the AC file your working on. You can paste it in either a newly created Worksheet or paste it in a Layout (i'd do this by specifically creating a Subset for Layouts that for external AC Drawing referencing). when you do either, you can Trace Reference into the plan drawing you're working on.