I go with a rapid alternation between the two states myself, especially since I think the pair of them will be pretty isolated.

In my own head, I figure that Council could actually "forgive" them being evil vampires deliberately putting their Slayers and Watchers in danger. What would be "unforgiven" is the fact that Xander and Faith was able to fool the Council (for a year in Xander's case)...which would make anyone hesitant to trust them, soul or no soul.

So in a weird way, Buffy's pretty much their only hope for ever getting out of the Council's version of the basement, which means they may be stuck with each other's company for a long time no matter how much their souled selves would wish otherwise.