Depends on room layout...and if you plan on placing a table/ottoman between them

it will work if tv over the fireplace...but if room is small maybe tv will be too high?

I agree with oaklands.......if the couches are perpendicular to the fireplace it can look very good but if you have to stretch your neck to look up to see the TV it might be uncomfortable.

The answer to your first question is that if the couches face each other you want room to navigate your legs to sit down. You will need about 18" to the edge of the coffee table which will sit between the couches. A small coffee table allows you to put the couches closer together......

Yes, the room would need to be quite large (min. 21 feet) in order to have a comfortable TV viewing distance while it is over the fireplace.