Frasier's apartment is draped from floor to ceiling with a stores-worth of decorations. There is no way a 30-something woman, and a 60-something man with a cane could have accomplished this. Nor would there be any room in their condo storage unit to keep it all.
After Niles walks past the automated Santa Claus to make him say "Ho Ho Ho," Frasier follows him, but the Santa does not respond accordingly.
In the toy store, Niles says Frederick will be arriving "in 22 minutes if he picks up a good tail-wind." Everyone knows that the jet stream only goes west to east, so it would be impossible to pick up a tail-wind coming from Boston.