removing the rotor from the 99 Cougar

No, it's apparently just seized. If you have removed the caliper and caliper bracket, it should come off.

Sometimes there are odd washers over the lug nuts up tight to the rotor. Be sure those are off, and the rotor should slide off. If it doesn't, some PB Blaster and a big ass hammer should do the trick.

Good luck.

Yup spray it down and let it soak, go do something else for awhile. Come back and hit it several times and it should come off. I just did this yesterday.