When Daphne shares some of her childhood keepsakes with Niles, he holds up a drawing of what he believes to be a turtle, but she says is her father crawling home from the pub. The paper Niles is holding is translucent enough to reveal that he is in fact holding a floor plan, possibly of one of the sets on the show.
Frasier claims not to know the names of anyone in the party crowd, but Noel Shempsky -- with whom Frasier has conversed on many occasions -- is present and plainly visible.