I know many people have posted that they are worried they can't build the broomstick graveyard. According to the list, you can't build that until you have welcomed Sally. There is a list in the app when you click on "This is Halloween" and then the second icon on the right is a check list. Click there to see the list of major tasks that need to be completed. That list is:
Dress to Scare: Get the Spooky Costume for Mickey
Halloween Fest: Build Jacks House
Welcome a Pumpkin King: Welcome Jack
Not THAT Scary: Take care of Oggies Bugs
Inspiration Strikes: Build Finklestein Tower
Goofy the Spooky: Get the Skeleton Goofy Costume
Halloween Fuel: Build the Candy Shop
Welcome a Creation: Welcome Sally
The Perfect Stage: Build the Broomstick Graveyard
The Scarer's Lair: Send Jack and Sally to take down Oggie in his Lair
Beating the Boogie Man: Send Jack and Sally to defeat Oggie in his Lair
Welcome a Boogie Man: Welcome Oggie Boogie.
I hope this helps.