Dan,
don't underestimate Musocity. He is a very smart guy (but sometimes needs a couple of beers).

If he didn't show the way to connect EZkeys to BIAB, it would be little use to me.
Don't get me wrong, it is a cool toy, but it is only becomes interesting to me personally if I can use it within BIAB for the reasons stated above.
And for the most part it works as expected.

The workaround for the re-routing MIDI is: export EZkeys timeline as MIDI, re-import file to Soloist. It does work, but extra steps, extra files. Obviously will have to be "re-saved" with every change made to BIAB chord sheet.

It would be very convenient if you can re-route that midi from EZkeys to another BIAB channel. That way you would be able to re-voice EZkeys to anything in your arsenal.