Re:site reports, yes I have but awhile ago, so it's a good idea to give them a reread. Thanks for the recommendation!
Re:sensitive questions, I've read many books on therapy (books designed for therapists, not clients) and study design for tough topics, but the only real experience I have is being a shoulder to cry on for friends. Definitely not an expert by any stretch!
However, I have been asking locals how best to talk about it and have steered clear of culturally taboo topics. I've also been asking local researchers with experience (including one studying the after effects of rape during the genocide in Rwanda) for advice. It seems that equipped with this knowledge it's not a problem because people seem to be voting with their feet. People come to talk to me after they've talked to others who have done so.
Factory farming - go to a factory farm and see what the conditions are like there compared to developed countries.
Ask locals what they'd want from us - ask Rwandans and charity workers what they think the charity sector is missing or what problems they want help solving.
Wild animal suffering - follow around certain animals and bugs in the wild to make notes of what an average day in their life looks like.
Ask locals what EA is missing - tell Rwandans and charity workers about EA and ask them what they think that we are missing / what our blind spots are.
Mental health professionals in the developing world - talk to a few mental health professionals about how mental health works in a developing world context and particular problems they're facing.
Family planning - ask people from a diversity of places (urban, rural, middle class, poor, etc) about their preferred family size and how they think about it and contraceptives. Apparently there is some data that many Africans have smaller families than they'd like.Some people think the high fertility rate of Africa is a large contributor to its economic issues, so it could be a fruitful line of inquiry.
Experience sampling for happiness - do experience sampling (a much better way of assessing happiness than the usual "how satisfied are you with your life?" question) of people to get a better sense of how happy they are on a day-to-day basis.
Rural animal welfare - go to villages (ideally ones visited by GiveDirectly or other GiveWell top charities) and see what the quality of life of the animals there are.
Mental illness in developing world - talk to those who are dealing with mental illnesses (such as depression or anxiety) and learn more about how that might be similar or different in a developing world context.