I don't have the energy or the desire to argue with your entire wall of text, but I especially disagree regarding the Unobtanium and the tree. He's said repeatedly that Unobtainium does a variety of cool stuff (hence its value), so there's every reason to believe that it's no accident that a dwelling was built over a large deposit of it. In fact, native populations gathering around seemingly unknown deposits of minerals is not unheard of in the history of North America (many of the largest deposits of natural radioactive elements were, or rather are, holy sites for several native groups).
Also, while I enjoyed it immensely, District 9 actually bothered me in how hard it was trying to drive home the fact that it was an apartheid allegory. Every damn sign may as well have read "THIS IS APARTHEID! DO YOU GET IT YET?". It was obscenely heavy-handed and I felt like I was being treated like an idiot, an hour in there were still "IN CASE YOU FORGOT THIS IS A LOT LIKE APARTHEID" moments. Essentially, I didn't find it particularly subtle. To be fair, I didn't think Avatar was subtle either, but that didn't particularly bother me.