Not sure what version of the 100 series you looked at, but I have not seen a 50/50 rear seat. The 3rd row dicky seats are 50/50, if that is what your thinking of.
The disco has a great back seat for 3 kids, the later version of the D2 has a 3 point seat belt in the middle. The 3rd row seats (which make it a 7 seater) fold into the side walls of the rear and don't block out windows like the rest of them do.
If you consider the jackaroo, be very careful, the diesel angine is bad, realy bad. Also the barn door opens the wrong way for the side of the raod we drive on, my Mrs struggles with it and it is why I hope to upgrade to a Pathfinder some time soon.
No matter what you buy, if you know the history it is worth paying extra $ for it.