I had started a Numbers spreadsheet of all of the versions of CodeWarrior using the Jonathan Hoyle info (in the link above) as a starting point. Then I went through the old metrowerks.com site snapshots at Internet Archive to try and nail down some missing release dates and extra info for each version, such as minimum host-OS version. I've even been trying to grab images of the box designs and datasheets for each version. Right now I'm focusing more on the later Pro versions since my target is PPC. The list is far from complete. It's a long process and I might never finish it, but it helps in my own searches.

Not sure if this helps but here's what I have for minimum host-OS version requirements:

Pro 5 requires v7.6.1

Pro 6 requires v8.6/v10 DP4 (last version to compile for 68K)

Pro 7 requires v8.6/v10.1

Pro 8 requires v9.2.2/10.1.3

Pro 9 only runs on OS X (v10.2)

One thing is for certain, copies of CodeWarrior, either disks or images, are amazingly elusive.