Wait, looking back I responded "no" to Ghost asking if it'd be about new people. How is this horribly offensive to you? I'm happy to discuss each of your questions, though...
1. That it would have a totally new cast
Almost certainly -- there's a huge disparity between TV and movie actors... no matter how much you hate Freddie Prinze Junior (and lets face it, everybody hates Freddie Prinze Junior) and love Mark Hamill, neither of them are going to be regulars on a TV show.
2. That it would have totally new characters
Almost certainly not -- it will probably follow the movie and WCA's dynamic of Blair and Maniac with various supporting characters.
3. That it would be like the movie
This is to what my Buffy analogy referred (or Stargate, if you're familiar with that series): similar in dynamic to the movie with many changes made.
4. That it would be like WCATV/WC1 in it's portrayal of the ships
Almost certainly not. A tiny, tiny, tiny percentage of people who would see a TV show would care that the ships were different from WC1. If *anything* it could use the same ships as the movie (I know, I know, go boycott whatever) because the high-res 3D models already exist.
5. That the movie cast would be returning
Again, almost certainly not.
6. That the game cast would be returning
Almost certainly not.