1. after about 15 miles of riding on rollers, my chain is now silent and shifts crisply. Today's 20 mile ride outside was perfect. So it looks like a little break in was all it needed or maybe it was just the lube working it's way in (although I liberally applied lube to the link when I spotted the initial problem).

2. as for link / chain compatibility, I'm running the 6.1mm version with a DA 7801 chain. The side of the box the link came in says "Compatible with connex 10S1, connex 10S0 and Shimano 10-speed chains"