I know it's too late for GICNJC, but for others reading this thread, here's the official answer from the Brazilian government. I found this by using the Air Canada Sherpa tool.
Tourism and Transit (VIVIS) — Ministério das Relações Exteriores (www.gov.br)
Transit in national territory: a VIVIS will not be required in case of a stopover or flight connection in Brazil, as long as the visitor does not leave the international transit zone and holds a single ticket (under a single booking reference, stating both the origin and the final destination, regardless of multiple stops or multiple carriers). If the traveller does not benefit from visa waiver and holds separate tickets, having to go through border / passport control when disembarking, s/he must obtain a VIVIS.