Can Lightroom provide most/all of the cataloguing features that Portfolio provides?
No, but that doesn't mean it's not adequate - even superior - for your needs. Things you can't do (at least directly) in Lightroom, vs Portfolio, with respect to cataloging features:
1. User-defined fields. If you want to create custom fields to hold additional data, you're out of luck without writing an LR plugin, and even then there are limitations (no writing the values to XMP!!)
2. No import/export of metadata, other than via LR plugins (again).
That said, I'm not sure what Portfolio would gain you in this workflow if those aren't dealbreakers - Portfolio lacks many things LR does easily.
- Roger Howard