I am curious about the the self heating reducing battery life? Is that because the temp of battery will not be uniform?1) The batteries will be in the unheated portion of your build, and will have to use the self heating function, so they won't last as long.
Or is there something in general with regard to the LiFPO4 chemistry at lower temps?
VS. big wires from the vehicle to the batteries in the back? Might be the same or similar. I suppose if reducing wire, then the placement would depend on charge rate vs discharge rate. Now if biggest discharge rate is an an inverter, then if inverter is also upfront in with the batteries, the long runs will be smaller ac wiring. If it's in the cold cab, maybe better for the inverter.2) with the rest of the components in the rear you'll need pretty big ($$) wires to feed the power to them.
I suppose it might be possible to modified the partition toto box them (w/insulation) in so they were in the heated space.