The Mirror Drive Door PowerMac G4 has an ATA/66 IDE BUS. So, that requirement is met.
The 80-conductor cable is simply that. It is a 40-pin cable with 80 wires.
Yes, sounds odd. But, it is actually a 40-pin connector cable with 80 wires running through it. The additional 40 wires are used to minimize cross-talk and enable higher-speed transfers with reduced data loss / noise.
If the machine didn't come with an 80-conductor cable, then one could be obtained for about $3 or less. I called my local store when I needed one, and was quoted $3. When I got there, they gave me an 80-conductor cable, and said no charge.
Well, actually, there was a fee. They asked that I make sure to refer people to them.
So, the requirements should be met. If the system doesn't actually have an 80-conductor ribbon cable, then just grab one cheap, and go with it
Edit: The machine is listed as having one ATA/66 and one ATA/100 port. Most likely the ATA/100 is used for the hard drive. But, either port will more than meet the requirements. Each port would handle two drives. So, two ATA/66 and two ATA/100 drives. Best performance would be placing the hard drive on the ATA/100 and CD or DVD writer on the ATA/66 port. This way you are not sharing the bandwidth between the two drives (by sharing a cable).