This is how I think would work out. From the beginning, you have the option as starting as Exile or Revan. I fyou chose Revan, then you are wounded and force drained on an Outer Rim Planet. If Exile, then the Ebon Hawk has crashed on the same planet, and is also force drained. In which you eventually find each other and go to where ever gives your main quest (I: Dantooine, II: Telos). After picking your Revan character, you pick Exile and vice-versa, since your going to be playing as both characters at different points in the game. Also, you choose what happened in KOTOR II and I. Like maybe in the Prolouge, another character has to program files of characters into a databank. Your going to have to rebuild both characters force, being that the constant fighting and all of that has completley drained the force out of you and you must re-establish it. Or someone has stolen it, like the Scepter of Ragnos in Jedi Academy.