I have a secret to tell you... the participants of the forum skipped the Geography classes to study English...
Let me try anyway...
1. Above the equator, the northernmost
state capital is Boa Vista
2. Traveling southwestwards
from Brasília, the first state capital you hit is Goiânia
3. Except for Porto Alegre, the southernmost
state capital would be Florianópolis
4. Below the equator and on the coast, the easternmost
state capital is Belém
5. You can practically walk southwards
from the Tropic of Capricorn to be in downtown São Paulo
ps1: southwards is misspelled in your message;
ps2: of course I looked it up in a map