Regarding the rear seat area, I don't think there are any vents back
there?

Yes, there are. They are on the side of the center "transmission hump" that
goes down the middle of the cabin, and are two vertical openings located
just behind the plastic flap handle housing.

If you can't see them, it's because some doofus probably carpeted over them
at your last interior re-do. I, too, had no idea that there were heat ducts
in the back seat, and my poor kids froze their butts off that first winter
we had our old Warrior. It was only after seeing heat ducts in another
Warrior that I started probing around with an ice-pick, found the openings,
and cut the carpet openings out with a razor.

Not surprisingly, this made a huge difference in the comfort of our airplane
in the winter! The small levers on the floor up front actually control
the front-to-back heat distribution on each side, so once you've cut the
carpet openings, make sure the levers are in the fully aft position.

Good luck.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"