Sophie B. Hawkins was actually born in 1964, not 1967.
Although Lassiter wakes up to the Archie Baxter's ghost alone in bed, a character appearing by themselves in a dream sequence is a common trope in film/TV, regardless of who they are physical with in the "real world".
(at around 35 mins) When O'Hara opens the door to Lassiter's office her left foot catches the floor, almost causing her to lose balance.