sfmans,
We are drifting again I'm afraid but just trying to sort out the terminology(caco)phonies. I did use the term "monophonic" a bit careless myself saying "monophonic type of instrument" meaning to point out that it is "suited for melody playing" in spite of its technical status as a "polyphonic" instrument.
We seem to agree upon that so far.
I don't know if these terms are established at all for categorizing musical instruments. When they commonly ARE used speaking of music (not the instruments) "polyphonic" means that the music has got *independent* part- or voice- lines, different from "homophonic, having voice lines bound together (for example in a chordal form as for hymn arrangements), and different from "monophonic,having just one voice line, like a single note "melody".

If using the terms in analogy for instruments, pianos and organs can be used for "polyphonic" music, the uilleann pipes can not, the optional chords by the regulators or the drones do not qualify them in that sense even though more than one note is sounding at the same time.

The English concertina can be used for some "polyphonic" music for sure but my point was that it is "NOT (suited) for combined melody and *independent* accompaniment". Compare the accordion which is designed for such purpose.