I'm very curious as to how accurate the outfits of the soldiers (or sailors I think, since the British, Spanish, and French navies are in the game) and the warships actually are, and if they share any resemblance to the 18th century West Indies between the years 1715 - 21 (when the game takes place) - Here are some images of them:
For some reason, there were images of Spanish ones in blue-white outfits, but they appeared yellow in the game, here's the Spanish in their blue-white outfits:
all enemies wore the same outfits both on land and at sea in-game.
Warships:
British brig and man o' war plus brig concept art but without the ram
Early (before game released) representations of Spanish ships
Privateer (also referred as "pirate hunters" schooner and brig
The Portuguese navy was present in the game (in one mission, they were involved off the coast of the Yucatan Peninsula). I couldn't find any images of any the Portuguese ships but this video of one of the game's main missions features Portuguese brigs, frigates, and man o' wars
I think I've commented on the accuracy of the material culture of this game on here a few times. The easiest way to sum it up is: The game did not go out of their way to portray the material culture accurately. They went with what their general audiences would expect and what would be functional for their game's levels and mechanics. They might pick up a generalization here and an interesting tidbit there, but the only thing you might say is accurate is not the material culture, but the attempts to try an incorporate as many historical events and people as possible into their story line (altered, of course, for entertainment value).