text Search, Copy/Paste, commenting is possible with HTML-based articles as @Anselm mentioned earlier. And text highlighting is not supported in ADV as @Adi mentioned.
Library(I guess custome store if you are talkiing about enterprise feature) is possible in the Customer viewer app with DPS Enterprise. If you don't see the option to customize your library in VB, guess you are not logged in with the correct credentials. Enterpise can customize upto 8 library icons and Pro can customize upto 5