You can't finish Toan's house until after you pick up the kitty on Floor 8 of the dungeon.
*Update*
I never had any trouble with this trophy myself, but from looking around at other sites after a comment here, apparently this one can be glitchy. Based on the quote I put in the comments, don't put down anything in Norune Village until you have kitty on floor 8 then complete and set down Toan and Renee's house only to avoid the possible glitch. Save first so that you can try again if something goes wrong.