I haven't read the TL, but if Brazil was English, with English-sounding cities, why do the rivers still have the same Spanish/Portuguese-sounding names as OTL? Sure the ones that start in Spanish territory like the Paraguay could stay called that, but the São Francisco and the Tapajós stand out like a sore thumb. Even if they were discovered by Portuguese explorers the names should have at least been Anglicized, if not outright changed.
EDIT: If the PoD was in the 1580s then there's no way some of those rivers would have the same names. The Amazon itself had only been explored and named 40 years before.
While I can agree about some things, particularly renaming the Amazon (hopefully going to get Reagant's help with that), I have to disagree with the bolded part. While Canada might Anglicize names, Brazil ITTL is more akin to the US as regards to place names. Which is why while the biggest cities shown on this map (this is ultimately going to be an inset map, not a big map, so it only shows BIG cities) are English-named, there are many Portuguese-named cities as well. And as for rivers, like I said I'll change major ones that NEED to be changed, but plenty won't be Anglicized. After all, in the US we have plenty of non-Anglicized major rivers:
Colorado River, More than Two States, (Colorado means Reddish)
Agua Fria River, Arizona, (Agua Fria means Cold Water)
Blanco River, Texas, (Blanco means White)
Brazos River, Texas (Brazos means Arms)
Calaveras River, California (Calaveras means Skulls)
Castor Rive, Missouri, (Castor means Beaver)
Conejos River, Colorado, (Conejo means Rabbits)
Escalante River, Utah, (Escalante is an Spanish last name)
Estrella River, California, (Estrella means Star)
Fresno River, California, Fresno means Ash (tree)
Frio River, Texas, Frio means Cold
La Plata River, Colorado and New Mexico, La Plata means The Silver
Leon River, Texas, Leon means Lion
Llano River, Texas, Llano means Plain
Nacimiento River, California, Nacimiento means Birth
Navarro River, California, Navarro is a last name
Nueces River, Texas, Nueces means Nuts
Pajaro River, California, Pajaro means Bird
Perdido River, Alabama and Florida, Perdido means Lost
Rio Hondo, California, Hondo means Deep
Rio Puerco, New Mexico, Puerco means Dirty
Rio Riudoso, New Mexico, Ruidoso means Noisy