Front O2's?
IMO I would weld bungs for the pre-O2's and run a wideband in the position of the post O2 and either get an O2 sim for the post or have it programmed out.
If your going to run a somewhat stock PCM (and even if your not I believe) you'll need the post O2's to tell the PCM what the A/F ratio is so it can adjust accordingly.

