According to Wookieepedia- you either join him, capture him, or exile him. But I think if you join him he remains in the shadows, seeing as he betrayed the Empire an all (he did, didn't he?).
As for Zhorrid, Wookieepedia says she dead - but has no source so we can't be sure.
Er not really when you join him he gets a parade to signify his return and because of his plan he became the prominent council member so then he could implement the changes he wanted.