You are trying to make Jânio Quadros blush?
There was no conclusion because everyone failed to find data about Brazil on the time, apart from someone that showed that Brazil didn't bought some jets. I for example commented that Brazil had some Ft17 stored and people simple concluded that the brazilian main tank was the FT17.
If there is a war and France calls EU, there is not even reason to invade because Quadros would retreat. If the war is between Brazil and France, then things get interesting. With alternate scenarios, just have France to fall for the nazis and a pro allied Brazil to occupy Guyana.
Edit: A brazilian page, "Hoje no mundo military" made a analysis of the plan, called "Operation Cabralzinho"
Brazil would advance with five motorized brigades, with a total of 2500 man, more than the french garrison on the French Guyana. According to the channel, that was more than the french garrison and more than enought to overrun the french province, plus the operation asked for in the months before the action they should begin infiltrating brazilian soldiers using the superior brazilian tactics on fighting on the forrest.
Then comes the french response, Jânio expected them to not react fully at first, he knew that De Gaulle was going to declare war but it would take time to assemble a fighting force due the Algerian front. With this two things come at hand: First, the brazilian army was expecting to coup the government for a while right now, they tried in 1954, 1955, 1957 and they would try again in 1961. The brazilian army didn't worked on loyalty, but in money, and so he De Gaulle could bribe some officers to remove Janio and restore a white peace. On the second scenario France can prepare a invasion and retake Guayana, the owner of the channel doesn't explain how the war would go, but he makes the point that the CIGS, the brazilian bureau reponsible for coordenating the operations on the forrest was only created in 1964. The main difference of this with the Falklands war is the fact that Guyana is not a island, and so you cannot starve the defenders, you need to assalt, and so we can conclude that France can win the war, they are the most likely side to win, but this is not fully garanteed and it would be dirtier than the falklands war.