A PowerBook 190 would be the best option for this as you can create a boot CF in the PCMCIA Slot with System 7.5.x. If it can boot from the PB190, it should boot on the CC. Keyword is "should," you need to install it as "Install for Any Mac" and not "Install for This Mac."

But in the case of the Lombard, you can use a CF to PCMCIA adapter in OS8 to partition and format the CF in HFS. But to install System 7.5.x on the formatted CF, you have to do it on the CC or a PB190.