Engine is a tight fit and you will need to notch or remove shock towers. If it has ABS and is an auto you will need to find someone who can "fix" the computer or it will go into limp home mode.
The dash and instrument panel can be installed (was done on a Mustang so it should work on a Cougar)
Wheels will fit with spacers
Front struts will fit with a fatman coilover suspension conversion
Rear axle can be adapted to suit