We are told that only Yater and Gilgaol can "seize" a soul, but I would imagine that the God-of-Gods wins out over of both of them (and I'm not sure where Ajokli fits into this but he must be up there). So far it would appear that acquiring the favor of the God-of-Gods results in Oblivion rather than a paradisaical type of afterlife, however.
So in theory, I think Yatwer could save a soul, but she might not ALWAYS be able to if she desires it, depending on who actually gets "first dibs" in the Outside.