By floor mounts, I assume you mean racing seats mounted directly to the floor? If so, there are several different types of brackets you can get, depending on what brand seats you have - what brand seats do you have?
For what it's worth, I've got Corbeau racing seats in my 95 coupe, with double locking sliders on both seats, and I fit just fine with a helmet on - there's not a huge amount of gap up top, but I can move my head around freely. I'm about 5'11" to 6'0". I don't know if the roof line is lower on the new edge, but I would seriously doubt it. Also, if your car isn't a dedicated track/drag car, I would recommend trying sliders first, as it will be a huge inconvenience to get floor mounts if you ever need someone else to drive your car or access to the back.
I have my seats out of the car right now for some work I am doing, I can measure things if that would help you any?