Latin American leagues usually happen in the winter seasons of Northern Hemisphere. Weather is conducive to it, and you're not playing in most of the US anyway at that time.
Being an alliance with only experienced veterans who know the culture of the game and about how stuff works is a rarity. Few alliances work on that scale; most majors do some form of active recruiting with brand new players, and that comes with upsides and risks. Elite culture alliances tend to not be large in member count for a variety of reasons, but one of the upsides is that you can be very free and open with members relative to groups that recruit from the masses.