First, the Phoenicians probably never reached Brazil and if they did it seems unlikely they did more than replenish supplies and try to figure out how to get home. It would be cool if they did but the evidence is at at very best questionable, circumstantial, and tainted with a lot of forgeries.
After that though, assuming they did manage to establish trading posts that eventually turned into a viable settlement I think the impact would be wide-reaching, dramatic, and what was created wouldn't be particularly Phoenician.
Considering the distance, difficulty, and availability of colony sites in the Mediterranean they'd probably be extremely lucky to attract a few hundred colonists a year. Of those the heavy majority are going to be men and they in turn will marry locals. Just like many Spanish colonies, within a few generations the population is going to be ethnically similar to the natives and might very possibly adopt local languages and customs as well considering their isolation and so few additional settlers each year.
Old World diseases are of course going to be a problem, causing much of the same plagues as they did in our history. On the other hand there's no wave of immigrants or conquistadors ready to take advantage of that. There's a lot of political and social upheaval but the population will eventually recover.
The biggest changes that will far out race the Phoenicians themselves are metal working and whatever livestock and crops they manage to bring with them. Goats, pigs, and sheep seem plausible but I'm not sure horses or cows would survive that trip (maybe?).
It seems likely that a Phoenician colony will mostly go native and eventually become just one city state in the vast politics of pre-Columbian Brazil and that their technological advantage will erode extremely quickly, perhaps within as little as a few years as the locals adopt it.