I had a similar problem using WSJT-X. Once I upgraded my Windows to 1709, I could not get my DAX to work on TX and the receive stream would only work on DAX-2 through DAX-8. Out of curiosity, I reverted back to 1703, and everything worked fine. I then, put my computer back to where there was no WSJT-X on the computer, upgraded to 1709 and reloaded WSJT-X and everything worked fine. I also tried removing WSJT-X on the non-working computer, re-loaded, and still had the same problem. It seems every time Windows makes an "upgrade" things go to hell in a hand basket.
1. Yes, Slice B fails when it is only slice.
2. Checked Device Mgr and all looks okay. Not sure what you mean by entries for DAX Channels?
3. One other important point is that despite the CAT and Radio connections being identical to all others and the "CAT Test" showing Green on the WSJT_X settings the front digital frequency display comes up in Red. On WSJT-X with the other working Slices the digital frequency displays are in Green.CAT setup appears to be identical to others...