brazil strong

I'm writing this thread as i feel like "US-pliant Brazil" is way too common a trope in AH circles. I'm aiming for a conflict in a 20th century level of tech, but i've out this in Before 1900 due to the PoD. So, assume that Dom Pedro II's two legitimate sons survive beyond the 1840's, into...

So, suppose that Brazil, in one of its wars with Argentina in the 19th century, gets lucky and acquires the regions of Paraguay, Misiones, Corrientes, Entre-Ríos, and Uruguay, forming a border all the way down from the Paraguay to the Paraná rivers. Here's a map for reference: So, what does...