To end the speculation…
I contacted the Inspirations’ office and found out that the fifth man who sang on stage with the Inspirations at NQC was Mack Clark; either Clark or Darren Osborn fills in with the Inspirations when Archie Watkins has throat troubles.
It is Mark Clark. I believe he was the one this weekend at NQC.
Thank you for the clarification. Sometimes northern ears have a hard time understanding southern accents! I will edit the post.