Coming up with a script - the CW only ordered the pilot. So, they're currently working out the main concept, the characters, the stories - and probably they themselves don't yet know many of the things we're asking about. Normally all the pre-production work (casting, location scouting, etc.) happens after the holidays (Jan-Feb), while the actual filming takes place in March. The decision whether to order it to series or leave it at pilot is normally made in late April/early May.