Tom:
 
Thanks for your observations.
 
The significant "Irish Tenor" in the background in the choruses is intentional.  The client wanted to convey a source of ancestral "highland" power being the essence of care and compassion which is represented by the vocals in that part of the song. 
 
In hindsight, it probably would be less "ambiguous" if one or more of the vocals had a "highland" style as well.
 
However, I do appreciate your comments regarding the "Irish Tenor" as the client wanted the "Irish Tenor" to be significant but not overpowering.  As such, I have it spread wide across the stereo spectrum (using the Channel Tools plugin) with significant reverb (Sonitus Reverb) to make it sound like it's ethereal and distant.  I used an exciter (HF Exciter) and EQ (LP EQ) to ensure that it cut through the mix even though it was in the background and on the edge of the stereo spectrum.
 
Incidentally, the "penny whistle", flutes and bass were tracked using (believe it or not) the SONAR provided Virtual Controller/Keyboard as input to Rapture Pro using SONAR provided patches.  The parts were simple enough to be able to use the Virtual Controller/Keyboard to lay down the tracks.  They were only supposed to be "example parts", but we were pleasantly surprised by how they turned out so we used them as they were recorded.
 
Thanks again for your comments.  Much appreciated,
Paul