I think these 1R matches are interesting aswell:
Tim Smyczek USA  vs. Tsung-Hua Yang TPE
Denis Kudla USA  vs. Daniel Kosakowski USA
Donald Young USA vs. Michael Russell USA 
Mischa Zverev GER vs. Tatsuma Ito JPN 
Yes to the all-American encounters. Zverev-Ito could be good too, depending on which Mischa shows up. But Smyczek ought to have no problems with Yang.