If she has to drive in the snow forget the LS. (stability control is overrated in the snow) Long term reliability isn't great in my experience. At 50,000 miles they fall apart.
The X-type will be cramped even for young kids and is a bit overpriced.
The S80 is probably your best bet. They had a teething problems but it seems they have cleared that up. You won't find anything safer. I would steer away from the T6. The torque steer can be pretty bad and in most situations the car isn't that fast. The AWD is nice. Its a peppy engine with a good awd system. I have driven the s60 awd a fair amount with this combo and it is really good all round. The s80 is a great long distance cruiser and gets good gas mileage if you don't push it too much. Opt for the surround sound system. Its sounds amazing, one of the best stock systems out. Also the backrest release is a good way to piss your kids off.
