Here's how it should shake down:
Yellow is an obvious ally, since he doesn't want to fight someone with a brai, (you). Make a border trues between North Afica and Brazil. This allows him to go after Europe while you can take his yellow in North America with no problem.
Obviously, no one will like brown, because he backstabs. North America is an easy expansion from South America, so split troops between Venezuela and Kamchatka. Brown is eliminated in North America.
Yellow goes after Green in Europe and blue eliminates brown by taking his Asia territories.
Since blue is isolationist, he won't care you took territory from him in North America. If he is angry, offer the rest of your Asia unhindered. He then eliminates green from Asia.
You and Yellow should finish off your continents at basicall the same time. What you do next is crucial. Hopefully, you never moved troops from your Brazil border and, even better, he did to go after Europe, (this is likely, since North Africa is right next to a Europe territory). You " nail" Iceland, citing it as a better place to defend than Greenland, (many territories can be attacked from Greenland). If Yellow tries to attack you, you can go backdoor and "nail" North Africa, which destroys his army totals, so Yellow will concede Iceland for now. What he doesn't realize is that he screws himself at this point in the game.
Whereas you have really only one front to protect, (Kamchatka shouldn't be too much of a threat from blue, and there's a truce in Brazil), and way more armies coming in, you have pulled off my favorite fortress: Frotress Americas. Yellow will have to either take Iceland, which will lead to you taking North Africa in response and all but eliminating Yellow, or he will have to go against Australia. Either way, though, he will be the next out.
You can more readily expand to Africa than Blue, because of your chokepoints, which means you now have three continents to his one. fortify your borders, keep one army in each other continent, and gradualyy finish Blue off.
Note, this does not account for cards, but still you should be in the best shape following this.