A lot of points here. Not sure I feel like the term “non-Christian” should be viewed as inappropriate… seems like a useful taxonomy to me… but much to consider. Ethnocentrisim/Imperialism, lack of cultural reciprocity, and rejection of intracultural missions are some important points here to take seriously.
By the way, I am not against short-term missions. But quality will bear better fruit than quanitity. The good can outweigh the bad if we make effort to make it happen.