Old thread. OP has either figured this out, or torched the entire thing. But, just in case anyone finds this thread in the future and needs to know:
The PC-DVD and Hex Speed drives are standard IDE. Mine work with all the IDE CD-ROM drivers I've used so far, typically SBIDE.SYS or OAKCDROM.SYS. The 48X is of course new enough that it'll be standard IDE as well, but I don't have one.
I don't know what the bottom drive is, but it has similar design language with a couple Sony drives that I have, so it might be a re-branded Sony SCSI caddy-loading drive. In that case, ASPICD.SYS or whatever your SCSI card came with.