I think I am qualified to answer your questions because I am a well informed immigrant living in the USA. Yes you are being paranoid. First there is no evidence to show the new administration doesn't like South Americans. Even if you're from Mexico which clearly this administration has some issues with, Mexico is not a South American country. It is in north America.
You are 25,employed working in the IT field as an Engineer. You have hostels, flights and attractions booked and printed. You have evidence you are employed. Don't worry immigration will ALMOST DEFINITELY have someone who can read in Spanish. You have your vacation approval email, bank account statement,Paychecks, Social security and individual tax identification papers.
If I assume correctly the dates of your bookings correspond with your vacation letter. You were issued a visa, so prima facie I would say you have shown you are eligible to enter the USA and with the documents you have, barring doing and/or saying something outlandish to the immigration at the entry points, you should be able to enter without a hassle.
Make sure you have a multiple entry visa because you will be leaving the USA into Canada and then entering the USA again in Anchorage.
Enjoy your hike.