I finally 100%'ed the game, and i went trough the guide and can add that Cochinay never gets unlocked, you go there once in a main story mission, but when coming back later, even after finishing the main story, the place is deserted, wich makes a total of 7 hideouts not 8.
Now I played it on xbox 360, and from what I've read it seems the PS3 version has an exclusive gang hideout which is Solomons Folly, so that would make 8 gang hideouts for PS3, I cant confirm that myself though, but if you do some research it seems that's the case.
I think that should be added to avoid confusion.