+1Revision to GreyViper's suggestion: After telling Irene about all of this, put down the shard in plain sight, back away from it with arms raised, and attempt to make contact with the child again. Assure it that we're not a bad guy and try to talk with it some more, maybe coax more information about the Third House, Avarlos, and "She" out of it.
(I really don't want to use the shard's power to find the mansion again - we might really piss "She" off if we come trampling into the grove again AND we don't know if the mansion or the keep is the Third House the kid keeps referring to.)
Heh should have thought of that myself.:D