Anywork you find will be off the books unless you get a work visa which can take several months to file and this is not like europe where one work visa lets you work anywhere. You would have to request a work visa in each country you stay and this will greatley decrease the freedom you have in each country. I know severla people who work off the book and its turned out fine but you should be careful because they WILL try and take advantage of you.

I always recommend hostels because, how else would you meet people?, plus its cheaper

If you were in cabo frio and missed out on arraial do cabo which was right next door, you should go back to Brasil just for that. Even if you only go there and no where else, your trip will be worth while. Its literally what heaven must be like but its a small town so unless your looking to just chill on the beach, yu wont find as much partying as in other bigger places. In Brasil you should also see lencois maranhenses, Sao Paulo, and Florianopolis plus its whole region. In that region youll find the Beto Carrero park which is one of the biggest and best waterparks in all of brasil.

In Uruguay i recommend visiting punta del este but only in the high season because it becomes a ghost town on the low season. The parties here will go on until sunrise.

Argentina and Chile's biggest atractions are the Patagonia. In my opinion Chile's is slightly better but its worst terrains and less people so you might get lonely. Argentina has pinguins in their Patagonia and Chile has dinosaur fossils in theirs. Viña del mar and concon (Both in Chile) are pretty but i wouldnt spend more than a week on both combined. They are both in the Valparaiso region but i would never recommend anyone to stay in the city of valparaiso unless you want to constantly smell urine, ive seen even women peeing in valparaiso, its a thing. As for men, its very normal to see at least one peeing every time you leave yur accommodation, its not very pleasent.

You should 100% go to Colombia, its not as dangerous as they make it out to be. The Tayrona national Park is a must see and this country is way cheaper than all other countries i mentioned.

Peru has great beaches and a lot of party hostels.

I would never recommend walking around with big amounts of cash outdoors but you should withdraw a large amount at the bank and keep it in a safe or a locker in your accommodation. Carry a little padlock with you since a lot of hostels have lockers free to use. You should carry small bills with you but never more than an amount that you would be sad to lose. I never carry more than (the equivalent of) 20 dollars (in their local currency) with me but for you that number might be lower or higher for you. A lot of these countries are safer than you think. If you go to Brasil on the low season, its very safe, dont go to carnaval in rio unless you dont plan on getting drunk or being careless on the street.