as well as in the wishing well and other locations... is it possible that it is all from the same source... I mean it's been used to travel between worlds, has many of the same properties... like through the waters of the lake and the well and where it maybe connected in other worlds, that maybe the walls between worlds can be broken?
I don't think so. They simply have the properties to bring things back. So Lake Nostros opened a portal because it brought the wardrobe ashes' properties back (and they scattered in the water thus opening a bigger portal).