[prewinter]

Here are comparisons of the two unknown players with Swartzel and Donahue. The mustache on the last player in the back row (Unknown 2) is what throws me a bit. But I think Donahue is Unknown 1 and Swartzel is Unknown 2. The slightly rounder nose on Unknown 1 seems to match Donahue better, while the ear on Unknown 2 seems to be closer to Swartzel.

Mike Mattimore was previously posited as Unknown 1. My feeling is this photo was taken before Mattimore joined the club midway into the series in Philadelphia.