I know what the conceptual passes are, but ZTC merged them, including the multiple conceptual passes the CPP does.

Those were not conceptual passes, but actual standalone programs executed in that order, to compile a C program. Each program operated within 64KB RAM, shared with the OS and all the drivers.

And Zortech C, for 64K machines, had two standalone programs to compile a C program to an object file.

Cudos to Zortech C