Keda,
as to the SCSI side, there are adapters for the ultra wide HD (probably 68 pin connector) to fit the internal SCSI ribbon cable (50 pin style) of the 5200. So you should be able to connect according to form factors, but I am afraid the SCSI bus of the 5200 will not take full advantage of the drive's speed.
With the CD drive, it might be another situation if your replacement drive is not an Apple one (or at least one with an Apple ROM). In this case, you need third party driver software to use it. This way, maybe you end up with a computer that cannot boot off a System CD-ROM.
Hope this helps,
Walter.