does factions and nightfall come with more charector slots?

simple quistion' title explains it all

When you add either of them to an existing account, you get 2 new slots. If you add both of them to an existing account, you get 4 slots total.

If you create a new account with either of them, you'll get 4 slots.

so i dont need the origanal campaign? of course id prefer havin my chars availble in all campaigns.. think im gonna go buy factions and nightfall tonight or tomarro

No, you don't need the original to play. But if you look around on these forums, most people will recommend Nightfall and Prophecies (original) over factions. If you're getting 2 chapters, those would be the ones to get.

You don't need the original campaign for Factions or Nightfall... But I would advise getting all of the campaigns and linking them together through one account. Not only do you get the extra character slots, but you are also able to make characters cross between campaigns and get access to the campaign-specific armor designs and skill selections. This can give your characters an extra edge as they can get a much larger pool of skills to draw from and offers more strategic choices.