Edit: So, I missed Ray’s Curren’s March 28th article at AWK on the Brazil-Canada match, which he attended in person. He notes that Brazil used a 4-4-2 formation, which does match the notation used in the CBF’s match report. Based on a closer look at some CBF news items on in-camp scrimmages earlier this year, it seems that new head coach Jorge Barcellos has been trying the 4-4-2 formation at least since January.
At this point, consider this post useful for historical, e.g., non-current, purposes. Although, with only a few months to go until the Olympics, it is possible that Barcellos may fall back to this formation.