1800 zetec conversion is going to be your easiest option the main parts you will need are
1800 engine and gearbox
hubs with drive shafts
engine wiring loom and all sensors
ecu non pats (passive anti theft system) pre 1994 1800 zetec
ecu to engine wiring loom
xr3i fuel tank fuel pipes hangers or similar
exhaust system
modify the engine mount (cut lug of for bolt 3 then re-weld or leave of
zetec radiator and early mk5 rad hose with fan switch
thats about it then it is the case of 8 or 9 wires to splice into your own loom
just watch if the ecu comes from a 1991-1993 car as some of them had external edis units as opposed to internal edis on later cars
the easy way would be to try source a full mk5 escort 1800 without pats then you will have pretty much everything you need