That sucks about the back. I've had back surgery myself and am currently in a bad spot so I feel your pain....literally!
Front passenger side cornering light, are you talking about the front amber blinker next to the headlight or the side marker? I'm going to assume the side marker as those can go out, the front blinker is just a bulb replacement. Side marker is a sealed unit, you'd have to replace the entire unit. They run around $100 each.
http://www.ebay.com/itm/03-09-Hummer...RWxdQE&vxp=mtr
Amber side markers are much easier to find then the rear red markers.
The rear hatch should just need the actuator, I'd be surprised if you need to replace the cables. Same thing happened to me.
http://www.ebay.com/itm/For-Yukon-Su...dVQJwe&vxp=mtr
I can't find the exact one I purchased but that one should work, double check the part number to be safe.
The door lock trim piece will be a little difficult to find. If it is something you can super glue I personally would go that route.
http://www.ebay.com/itm/Chrome-Bille...RSW2Kw&vxp=mtr
That is a chrome billet part and I'm sure a hell of a lot cheaper than a full OEM replacement. Could always scuff and spray paint it black. I didn't see any OEM parts from a quick search.
Hope all that helps and I hope your back starts feeling better. I just ordered an inversion table as recommended by the doctors I work with and the PA who saw me in office. I am very optimistic and can't wait for it to get here!