If you are using a zetec cam it will have the lobe for phasing ?, so just keep zetec sensor wired to P8 it will work as it receives a signal.
As far as I know all zetecs and cossies are sequential so will have phase sensors, and where they are is not relevant at all, if it has a phase sensor lobe machined on the cam it will give a signa, should be the type needed for P8.
CRANK sensor and PHASE sensor are BOTH needed for sequential injection, NO it will not work with just the crank sesnosr as ECM is looking for a phase signal as well, if it did not need a phase sensor it would have to be BATCHED FIRED, I am sure the P8 is not.
tabetha