Misko, when your character leaves the clan, she takes her life-essence along. As it is apparently a volatile item, it disintegrates once not embedded in the clan house foundations. If you look around (perhaps after leveling), I'm sure you'll find some of the ingredients lying idly.
As for the people stuck in the clans with absent leadership, all it takes is at least one deputy who is still active - she can admit a sufficient number of new recruits/insurgents who can then execute a coup from within. If there is nobody who can do that, perhaps mods could help - provided there are any of them still around.
Otherwise, leaving such a clan and starting a new one from scratch seems like a sensible course of action.
EG