Just to reiterate, the difference between active/inactive slots is discussed in the November update, and elsewhere in the forums. If you have any other questions, they will be answered on this thread.
When you log onto live, you will see you have 8 active active character slots. We have a new character slot system on the backend, with the intention of giving out some number of free additional slots to subscribers. The server code is currently patched out, but it will not be turned on when the patch goes live. We decided we have enough to test as it is, and the server migration is a big enough thing on its own.
I have been in discussions with Joel as part of the transition, and we are looking to increase character slots for subscribers shortly after the Migration goes through and we are satisfied we have dealt with any and all issues which may arise from that.