Hi Wiiville-
I have been travelling to Brazil for decades, and take gifts for friends and relatives each time I visit there. It is a friendly custom of ours, and other visitors, and we have never experienced a problem.
Just take what you can in the way of documentation, and fill out the form for anything in excess the $ 500 USD amount.
If you are customs inspected, you are in compliance, and have nothing to be concerned about. Just be open, honest, and friendly with the inspector.
If you are not, then continue on your way and enjoy your trip !