I do not know the cargo version, but if there is no rear well at the hatch then the 3rd row seat for a Freestar will not fit. You may be able to install a Windstar 3rd row but it will require obtaining all the hardware and a cut an fit install.
3rd row back attaches via hinge system in well and to latch rings in the side walls when flipped in to riding position.
2006 Freestar SEL 4.2L F/Ld - Wife still trying to wreck it.
2002 Ranger Edge 3.0L extd - My Sons Truck now.
2005 F150 FX4 SCrew - My new Baby