Yes, well then I don't understand why you ask the question. Take the he Lord of the Rings, the Silmarillion. Everything was predestined by the song of Eru. The Iliad ? Troy was destined to lose, but the Gods wanted to allow a decade of battle... and so forth. It's a myth/fantasy theme.
You were the chosen and so the surviors of the nautiloid crash that you were on were selected to help you on your quest.
We have Shar, Selune, Jergal and Mystra all getting involved, so something important is happening, and mundane things might not matter so much anymore.
Yes, I make this stuff up in my own head. You ask others to explain this to you, and that's what I just did. Do you want an explanation that is not made up in one's head ? Then you'll have to ask a headless one.
To be clear.
What reason have you come up with for why these gods need everyone to have ties to Baldur's Gate?
IMO, it's because of (1) writing choices and (2) due to the limitations of the game graphics (we get part of one big city rather than multiple cities or settlements), and the city being in the title and at the endpoint of the game, they just tied everything back to it. From a writing standpoint, IMO, the plot is weaker than in some other crpgs because it's trying to juggle every companion having main character syndrome. (I dislike the origin character thing and think the best crpgs have a set main character, though, so that's my personal opinion).
