Not too sure but I don't think the CVH exhaust manifold will fit the Zetec head
You should be able to seperate the Zetec engine loom complete with ECU plug without too much trouble.
Or you can do what I did Chop through the loom in the engine bay & kid yourself that you can shorten & re-join them later ...... Just to find that most of the wires in that huge bundle share the same colour codes
After several days of research at least I know where each wire goes !!??
Alternator could be re-located or replaced by the much smaller Nippon-Denso unit ( My choice )
On the subject of an age related plate ..... In theory, if enough parts have been used from the donor vehicle, it is still possible to get an age related plate if the donors engine is not used.
That said, it will probalbly be down to you to convince your local DVLA office that this is the case. ( Probably going to cop a bit of flack for this statement
)