;-) For what it's worth, I've gotten the setup working, so I'm mostly happy. Termination had indeed been the key. I have one bit of circuit board with connections for 68 pin SCSI, 50 pin SCSI, power, and a weird connector that resembles a card slot, in miniature, with about 80 conductors. The 50 and 68 pin connections have sockets for termination resistors, three next to the 50 pins, two near the 68 pin connector. Putting resistors into the two sockets next to the 68 pin connector did the trick.
:-? However, the rest of the setup goes contrary to normal expectations. My SCSI chain begins with the Cyberstorm controller, then to the powered terminator/adapter. A fifty conductor ribbon continues from there to the CD-ROM, which is terminated, and from there to an external connector at the rear of the A4000. From there, a cable is connected to the SCSI hard drive, which is also terminated. The whole thing works, whether the outside hard drive is hooked up, or not.
I chose to connect the CD ROM to the fifty conductor ribbon instead of using a simple adapter plug because, as many already know, there is not enough room between the rear of the CD ROM and the power supply to fit the adapter.
Hopefully, upgrading the FlashROM will permit booting from CD to work, but I wonder. When mounting the CD from ROM, the CyberStorm seems to use its own file system, and the CyberStorm file system doesn't support Mac or Linux format CD's, while later file systems available to AmigaOS do. So it's a bit of a trade-off.