It would be helpful to know what kind of CD drive you want. I can only assume that you want a straight up CD rom drive. Assuming that you will have to purchase an external SCSI drive with a PowerBook scsi cable. Yes, you can get an adapter for a normal scsi cable, but I don't recommend that because a dedicated cable with the PowerBook scsi end on it is your best choice.
I would check with these vendors: ClubMac, APS Technologies. They both sell drives in external enclosures that should work well with your system.
Theoreteically you should be able to download the software you want from the Cannon web site. Japaneese companies that make many different products often suffer from having large web sites that are hard to navigate. Just search on their core site and follow links that seem logical. That is the best advice I have for finding your sofware.
My guess is that Graphic converter isn't going to interface with your camera, which is what you need to do to get the photos off from it.
For people with older Mac hardware that want to participate in digital photography, I always recommend the Sony mavica because it works well with all computer that have floppy drives and the image quality is about as good or better than many low end digital cameras.