Bi-wiring with unterminated speaker wire?

Yes, you can!

Yes, and I’ve often wondered if bare wire is a better and more pure connection versus introducing more connections and different metals by adding spades and plugs — not to mention the added expense of doing so.  Go for it!

HI Soix- you can stop wondering.  Bare Wire connections ARE the best performing for a wide number of reasons.  Here's the catch- bare wire is the best connection possible for a VERY short period of time.  Unless the bare wire connection is treated and/or sealed, it will very quickly start oxidizing and the performance will suffer.  That is the main reason for formal terminations- you can seal the connection and dramatically slow down the oxidation effect ( notice I did not say eliminate it).

+4!
Just be sure not to short anything inadvertantly- though your amps fuses should reduce any chance of serious damage.
Bob