No, they are not. Star Wars Miniatures are created by Wizards of the Coast (http://wizards.com/) but the flat packages named Battle Packs are merely cheap copies, and have nothing to do with the Wizards' version of the game.
Yes.
Depends on what kind of miniature it is, who the manufacturer was, and whom you're selling it to
For collectable items such as Star Wars Ship miniatures, auction websites like eBay are great, as there are always interesting items in the collectables area. There are also specialist websites such as Boardgame Geek, which sell many similar items to this.
The Dharma of Star Wars was created in 2005.
Generation Star Wars was created in 1994.
Star Wars MUSH was created in 1992.
The Star Wars Corporation was created in 1976.
Star Wars Insider was created in 1987.
Star Wars Celebration was created in 1999.
Star Wars Arcade was created in 1993.
Star Wars Weekends was created in 1997.