Although supposedly based on true events, and the doll being a real object now kept in the artifacts archive of the Warrens, the end credits state that "The story, all names, characters and incidents portrayed in this production are fictitious."
The movie takes place around 1969-70, yet occasional newer vehicles appear throughout the film. In one of the earlier shots, there is a 1973 full-sized Pontiac parked at the curb.
When Mia moves into her new apartment she hears noises from the apartment above her but when Evelyn jumps out of the window with Annabelle you can see that the window she jumps from is the top floor window.
Are the brother and sister children on the stairs young Ed and Lorraine?
A
No. The film is set about a year before the events of "The Conjuring". The priest refers to the (adult) Warrens at one point in the movie as people who could help with the possessed doll. The children are never identified directly but some suggested they are the child selves of the two Satanists that died earlier in the movie.