Also, I´m so upset about sending a mail with all my documents to Brazil. To give you an idea, all the times I tried to send anything from Canada to Brazil, they got lost in the limbo...
If you applied outland, you wouldn't be sending your application to Brazil. It gets sent to Mississauga first to assess the sponsor, and then Mississauga forwards the entire thing using their own special diplomatic courier to the overseas visa office. True, if you somehow missed something and Brazil has to ask you to submit additional documents, you'd still have to courier them to Brazil. But that's just one of many reasons to do your best to make sure everything is complete beforehand.
Another point is that, by sending the "Change of Status" form with the PR application, I will get my work permit when the first stage is approved, right? My main concern now is that I can´t work here yet (even though I have 2 degrees, specialization courses, it´s so frustrating...).
Yes, you could apply for an open work permit (OWP) at the same time as applying for PR inland -- but you wouldn't be eligible for that OWP until you got first stage approval, which takes about 10 months right now. Whereas if you applied outland, you could be completely done by then. Not to mention that you can still leave Canada if something came up that needed you to without jeopardizing your PR application, and outland has right of appeal.