> Yes, it's completely valid to mix and match in this way — and these two
> standards address different aspects with the understanding that they
might be
> used separately or together.

I think Esmé is correct here (as usual!). I would just caution that it is
important to take a close look at the ontologies or RDF schemas that define
these terms in order to convince yourself they are really compatible and,
if so, at what level.

An ontology (and both PREMIS and BIBFRAME are defined as OWL ontologies)
may define constraints that, if violated, would cause problems for semantic
inferencing (not that lots of people in the cultural heritage space are
doing things with inferencing out there, but that's a separate issue).

For example, looking at the definition of a PREMIS IntellectualEntity (
http://id.loc.gov/ontologies/premis-3-0-0.rdf), it's not clear to me that
something could be both a BIBFRAME Work and a PREMIS IntellectualEntity. In
PREMIS, IntellectualEntity is a subclass of Object, which is defined as a
"discrete unit of information subject to digital preservation." The notion
of a Work in BIBFRAME (and the LRM, etc.) is much more nebulous and
conceptual. It would make more sense to me in a digital preservation
context--although I'm by no means an expert--to create relationships to a
BIBFRAME Item, which is the thing that is ultimately being represented by a
digital surrogate.

All best,
Tim

--
Tim A. Thompson
Discovery Metadata Librarian
Yale University Library