Xianburke

OK, the mystery has been solved. There's probably a bit of guidance that could be added to the Interwebs (documentation, YouTube, etc) somewhere.
1. The 'midi' or 'hub' flash on the Deluge screen only shows up if the Deluge is already turned on. If I add a device while the Deluge is on, then the display flashes accordingly.
2. I made a stupid mistake on my Keystep. I used a USB power cord, not a USB power+data cord. OOPS. Plugging the Keystep directly into the Deluge via USB power+data cord worked!
3. I have a powered 7 port hub (Ports 1-7) with an 8th port (Port 0) using the connected USB cord. I plugged the USB cord into an adapter then into the Deluge. The Deluge flashed 'hub'. PROGRESS.
4. Still only one device (Deepmind) worked. I figured out that it is because the Deepmind was plugged into Port 1 on the USB hub while the Beatstep and Keystep were in Ports 6 & 7. When I relocated the Keystep and Beatstep into Ports 2 & 3 on the USB hub, everything came alive! So, the lesson here is that only Ports 0-3 on the USB hub are actually seen by the Deluge.

I NOW HAVE A WORKING USB MIDI SYSTEM!

I hope this helps others.