Actually, I'm pretty sure the house is just Liar X. Agerate's house and the sign is nothing special. I could be wrong though. As for a Zelda reference, the moon might be grinning, but I think someone already said that it has Giygas's face in it. Wait though, does Giygas have a face? I mean, maybe Giegue, but not Giygas.
Yes, I consider Giegue and Giygas to be somewhat separate entities. Kinda like Ganon and Ganondorf.