All the CP/M binaries are for the 8080, not the Z80. The only place you might find Z80 code in a CP/M system is the machine-dependent I/O code in the CP/M BIOS. That will necessarily be different for any 6502-based computer hardware, and need to be rewritten, anyway. Or in the third-party apps. Though even there, most of the third-party companies restricted their software to using only 8080 code so their user-base was as large as possible.
The important part of the CP/M architecture was the thousands of independent apps that used CP/M as their underlying OS.
Very probably, the best 6502-based approach would be to keep all the CP/M system software and apps as 8080/Z80 code and use a 6502-based Z80 emulator. The BIOS itself could be replaced with native 6502 code as it uses a jump-table for the entry points.
So it might not be very easy at all, depending on how clever the people who wrote it were.