Thinking of moving to Buzios with my wife

May check Shell international. No upstream but have sales for downstream, but dealing with Brazilian vendor so language may be an issue.

Honestly, pretty crappy.....it's tough for everyone right now, unless you went to a Brazilian University you are at a real disadvantage of getting a real Job.
I would say basically non existent except English school

I've never seen a gringo working a low level job like floor salesman, I've seen one or two Paraguayans, or from somewhere like that working at mcdonalds
But honestly most people will just laugh at you outright, the idea of an American working such a low pay job in Brazil would just be an outright joke to them.

Most people really on Teaching English, or finding some other hustle, possibly tourism, or some other special skill you may have,  but it's tough, guides need licenses etc.

You are a Sales Pro and want to move to Buzios????  Unless you plan to be a host to some B&B or tend the bar, or work on the kitchen, or work on the sales counter for totchkes, you are wasting talent and won't find anything suitable. 

Mid size to large metro hubs is where the action it is.   Get sponsored by your US pals.   
Open up a business. 

And do not expect to depend on Brazilian help to get anything delivered in a deadline and on spec.  Whatever you can do on your own, then do it.

If I know anything about Texans is that they have swagger, like New Yorkers.  And that, while I see as a sign of self confidence, they might read as cockiness. 

My advice is that if you want to learn a racket, take up a job at the bottom rung, learn the peculiars, eat crow, and then hang your shingle.   And knowing you will be taking a scan pay rate.   

Also, look out on trends.  With the escalating costs of retirees living in the US, healthcare, and necessities, you may want to consider to open a beach head for your fellow expats. 
Colombia, Ecuador, Costa Rica and Mexico are cashing out on this, maybe there is something in it.   

Or else, tell your sweetheart to take a piece of humble pie, and learn to be a real American.  The adjustment here can be quite rought for neophites.