I think your balloon idea has some merit. For much of the early fall, very little gas would be needed to support a very large balloon that would retard the fall and limit terminal velocity. If your velocity stays low from the start, you never have to worry about heat building up. As the descent continued, eventually the atmosphere would thicken to the point that the balloon provided actual buoyancy, and subsequently a controlled descent could be made. Perhaps two balloons would be required, one weak, large one for the initial fall at the edge of the atmosphere and another stronger one for the final descent through ordinary weather conditions. The question is, how big would that first balloon need to be at the altitude of the space station?