While I'm at it: Do you know of an OLD 140mm, silent/quiet 7/8s hub I could use instead of the no-name hub the bike came with? Grease on the freewheel does dampen the noise… for a while, so a permanent solution would be nice.

if not available, a more common 135mm can do as shown with the Alfine 11. It only takes a couple of spacers on each side to fill the gap, along with spacers to move the disk caliper inboard