-
any benefit in trying to find a bushed chain
Very little. There might be a small gain in drivetrain life, and an even smaller gain in efficiency, but the former is negligible since the components are cheap to buy and quick to replace (cf. industrial drives where taking plant off line for an hour can cost thousands of pounds, so reducing the frequency of replacement is worth spending money on) and the latter is a concern only if you've already done everything else; it's hunting in the weeds for tenths of a Watt.
Those are all bushingless - any benefit in trying to find a bushed chain e.g. Wipperman 7R8? Unfortunately KMC don't seem to do any bushed chain in 3/32", only for 1/8" (e.g. X101).
PS apologies for the dredge...