If I remember correctly the L brackets for the roof mount stuff are all in place on the TB as well. I utilized the cross brasses behind the headliner to mount my screens. Used 16 gauge sheet metal and rivets to hold the mounting plates, and riveted the sheet metal to the braces. I did it over the course of a week, total time about 12-14 hours. Getting the headliner out is a PITMFA, thankfully I did not crease it.
Headrest monitors would be a breeze and I would recommend those as a great alternative, you can even pay the big money and get color matched interior, or you could find a set of factory ones and mount the screens yourself. Either way aftermarket has better options than OEM.