faerun is very easy for a dm to work with...a good way to go with a CRPG is to make the player or party special in some way...

it seems to me that throne of bhaal was supposed to be the end of the series, and to make it a true sequel, you'll have to stick with the bhaalspawn thing...

i would want to start fresh because it's easy...

you could do a prequel or a sidestory that happens at the same time as one or both of the other games, but they couldn't be as epic in story