Mr Light wrote:
<< Seems doubly odd since he was an original character, and they had a blank slate for casting him with no preconceptions from the comics.>>
He was a character from the comics, but an entirely obscure one who didn't have powers.
I thought so at first as well, as it turns out, not so much.
Amongst other interesting tid-bits (Including Coulson's cellist and connecting the story to Iron Man 3), there is this...
J. August Richards' character "Mike Peterson" shares a name with a character that appeared in a Marvel comic book called Slapstick. Was the name an intentional homage?
No. We found that out later! There's a whole bunch of characters with other names... some we do intentionally but that was completely an accident.
ETA: Ah! Beaten to it! Oh, well...