Dear Professor ,
Always nice to hear from you. The questions you asked are best answered by someone in Brazil, but most of the answers can be found already in this thread , these are however remarks made by individuals on internet and might not be the real picture . As far as we are aware CENIPA is conducting the Accident Investigation as per ICAO Annex 13,. Nothing else. The police investigation is another matter, and law in Brazil is particular. For instance a Judge in a very small community in Mato Grosso seem to want to make a name for himself.
The journal of IFATCA (the controller magazine at
http://www.the-controller.net) had a good series or articles in its last March issue, and I am told that another series of articles on the legal issues of this accident is due in their September edition.
Good luck,