Hi and welcome to the forum.
Yes the info is spread about a bit but a good place to start would be the Design Decision Archive
HERE
But a quick answer would be.
The Galaxy will be massive 100 billion stars is the current understanding.
Trading will be extensive across the galaxy as well as it's one of the staples of the elite universe.
Multiplayer will be a big part of the game as well, Finally release dates Alpha testing should start next month with betas early next year and the game is set for a March 2014 release for "gamma" release for standard kickstarter backers.
Have fun on the forum.
