And are the translations made by Brazilian Certified Public Translators valid outside Brazil?

It varies a lot. Even inside Brazil, depending on the agency, be it public or private, some demand certified copies of all documents, while others don't; some require notarized signatures, while others don't. Each one goes by its own set of rules. As we've seen, no Brazilian government agency, office, division, whatever can accept documents in a foreign language; this is what Brazilian laws determine.

Every other country will have its own laws and, if these are more tolerant in this respect, each governmental agency in these countries will have its own internal set of rules. Therefore, one should ask directly the authority where the document will be submitted. Don't expect the Brazilian Public Translator to know it all. At best, he or she might give you some guidance only if they ever had a client going through a similar situation.