Welcome to planDisney, Nicole!
How exciting that you're planning on attending the
Oogie Boogie Bash. You'll be mesmerized by the
Frightfully Fun Parade, as Disney villains join Mickey and Minnie for some Halloween fun. Also, make sure you check out
Villains Grove at the Redwood Creek Challenge Trail. My kids love this trail (and I do too!). The Disney villain theme is sure to have your entire family captivated.
Nicole, kids under three years old are considered "Guests of Mickey" and don't require a theme park ticket or park reservation. However, children above the age of three need their own ticket. It's a bit tricky in your situation since your child will be turning 3 during your trip. The official policy at Disneyland Resort is that Guests should book their vacation packages, purchase tickets, book hotel accommodation, purchase insurance, etc.,
using the age the child will be turning while traveling. Therefore, the official policy is that your child would need a ticket for each day you plan on attending the parks, including for the Oogie Boogie Bash. At this time, Disney doesn't require children to carry ID in order to enter the parks. Guests are expected to adhere to these rules using an honor system.
I hope that's clarifying, Nicole. Have a grim, grinning good time! Enjoy making lots of memories together.
Mike