As you know, post-conflict multi-lingual settings can be very sensitive areas, particularly in early, needs assessment stages with your work. This can be particularly true, depending on the tensions that likely exist to some extent, and the top needs of one group may not be the same as others. We are not aware of specific tools or guidelines for needs assessment in these settings, although they may exist. Of course instruments that have been translated into the languages existing in your region of the world have a major advantage. One recommendation we would make is that you think about, at first, holding multiple and separate sessions. We would not advocate segregation of any sort, but if there are factional divisions, it may be worthwhile, in the needs assessment phase, to have the events occur separately. This can avoid problems based on language and if the needs assessment sessions are made as equal in time and attention, that is always beneficial. In later stages of needs assessment or to obtain additional feedback, you can consider bringing separate groups together with appropriate translation, if that is possible and if you think it makes sense. Once you have a sense of some of the common needs across groups, you can present that to everyone and move on from there.
