Great writeup! I'd be interested to see how it works out for you long term. For many years we offered the aftermarket cast units however they seemingly failed more often then the OEM units, in nearly every case breaking at the notch for the lock lever. The rounded edges of the OEM unit could offer less of a stress riser on the cast? Its hard to compare as it really comes down to how the rear hatch is adjusted. If the latch mechanisms are super tight and the handle is pulled too hard to open, either of them will break.
Fwiw, shop around... the OEM is only $20 more at some places