Generally you should be able to add your Hilton membership to a Impresario/Virtuoso/etc booking so you'd still have status recognized. I had Diamond benefits stack with Virtuoso when I stayed at WA La Quinta for example.
Re what trumps what, generally I'd always try and book a client on the hotels on program rate if possible. Sometimes benefits aren't like for like, but a phone call can sort that out. Amex FHR comes into its own with the 4th night free which would be better value that a lot of own hotel programs, I just call the sales team though and they'll generally be open to giving me the same offer.