Not sure what's happening there, but, some things to check:

Check the cabling and jumpering of all drives. Linux is very picky about this. In particular, don't use cable select. FWIW, the master device can go to either of the end connectors, the slave must go to the middle and jumpering must be appropriate.

The CD-RW will probably enjoy being the secondary master.

Of course, after you've finished tweaking, you'll have to re-set the bios for the drives to show up to any OS.

External enclosures can be a PITA: does lsusb show up anything interesting?