Would the 867Mhz DP work for classic and OSX

Yes:

http://www.everymac.com/systems/apple/powermac_g4/specs/powermac_g4_867_dp_mdd.html

*This model is capable of booting Mac OS 9 and using Mac OS 9 applications within the Mac OS X "Classic" environment provided with Mac OS X 10.4.11 "Tiger" and lower ("Classic" is not supported starting with Mac OS X 10.5 "Leopard").

That Mac is capable of Leopard! However, Classic will only run under Tiger. I am not sure if OS 9 will run natively on that Mac. Perhaps someone can chime in if they know.

As stated above by Zotaccian, yes it can boot into OS 9.

I didn't realize there was a mac that could boot OS9 and Leopard10.5 natively!

Yup the G4 Mirror Drive Doors are the last PowerMacs that can boot into OS 9; and having a CPU that runs at or faster than 867MHz, it passes the CPU clock check Leopard does while installing.

jrsx said:

I didn't realize there was a mac that could boot OS9 and Leopard10.5 natively!

Click to expand...

yep, there were a handful of models that could.........even without the leopard hack.

Got to love how the old Macs had such backwards compatibility.