I think this grammar point needs more explanation. As it is it looks the same as について or に関する but there is an emphasis on a point of contention with をめぐって. It is used to draw focus to the subject of an argument, debate, conflict, etc. Perhaps a better way to define it would be to say (The argument, debate, conflict etc) is about...
In the third example, since されている the passive tense is used, shouldn't the translation be "the necessity of the new building is being discussed" instead of "they are discussing"