Great job and wonderful information!

Brazil has different accents and cultures. There are many linguistic variants.

For example, there are many "discourse markers" that show emotions or surprise too.
— The "too" is not needed and adding it here makes the sentence awkward. Also, in traditional English grammar, when using "too," it is always preceded by a comma following the previous word: "surprise, too."
I suggest you use: "...show emotions or even surprise."

In the northeast, it´s common to use "oxente!" = "ó gente". In the south, its common to use "bah" = "barbaridade". In Minas, we use "uai" = "why".

This expression is an English inheritance from the people that lived here in the 19th century.
— A better sentence: "This expression is of English origin..." - or - "This expression was inherited from the English people who lived here in the 19th century."

So, [here is common expressions] like "Why not, uai?" or "What a surprise, uai!" :-)

— Beginning a sentence with "So" is very informal and non-standard English and would only really be acceptable in spoken English. A more acceptable informal use of "so" would be: "And so..." But in writing it would be better to eliminate it altogether: "Here it is common to hear expressions like..."

Nice work and quite informative!