Just checked the HUB, here are all the details:
Parade, Fireworks and Other Merriment Club Tinsel Character Dance Party (Cosmic Ray’s Starlight Café)...............................................7 p.m.-12 a.m.
Kringle Crew Pre-Parade (Center Street and Main Street Train Station).....................................Prior to Parade Mickey’s “Once Upon A Christmastime” Parade (Step off in Frontierland)...............................8:30, 11 p.m.
Holiday Wishes – Celebrate the Spirit of the Season....................................................................10 p.m.
Once Upon a Time (Cinderella Castle)….........................................................................................12 a.m.
The Notorious Banjo Brothers & Bob (Frontierland)…......................................7:45, 9, 10:20, 11:40 p.m.
VoicePlay (Rockettower Plaza Stage)..............................................................8:05, 8:55, 10:15, 11:10 p.m.
Stage Shows
A Frozen Holiday Wish (Castle Forecourt Stage)......................................................................6:30, 8:15 p.m.
Mickey’s Most Merriest Celebration (Castle Forecourt Stage).........................7:40, 9:25,10:30 p.m., 12 a.m.
A Totally Tomorrowland Christmas (Rockettower Plaza Stage)...................7:40, 8:30, 9:20, 10:45, 11:35 p.m
Character Greetings:
Main Street, U.S.A.: Santa Claus, Mickey Mouse, Tinker Bell
Adventureland: Aladdin, Jasmine, Genie and Abu, Captain Jack Sparrow, Peter Pan (roaming)
Frontierland: The Country Bears (roaming) Liberty Square: Jack Skellington as Sandy Claws0
Fantasyland: Ariel, Rapunzel and Flynn Rider, Cinderella and Prince Charming, Belle, Pooh and Friends, The Seven Dwarfs, Snow White and her Prince, Aurora and Prince Phillip, Princess Elena of Avalor, Minnie Mouse, Scrooge McDuck, Donald and Daisy, Santa Goofy, Mary Poppins, Bert, Princess Tiana and Prince Naveen
Tomorrowland: Nick Wilde, Judy Hopps
Complimentary Holiday Treats
Adventureland Tortuga Tavern • Hot Cocoa and Snickerdoodle Cookies
Liberty Square Heritage House • Eggnog and Ginger-Molasses Cookies
Fantasyland The Friar’s Nook • Snow Cone and Sugar Cookies Pete’s Silly Sideshow • Apple Cider and Sugar Cookies0
Tomorrowland The Lunching Pad • Hot Cocoa and Peppermint Bark Cookies
Complimentary holiday treats available until 12 a.m. at the following locations: Alternative healthy options are available upon request
Special Offerings
Specialty Food
• Plaza Ice Cream Parlor: Peppermint Hot Fudge Sundae
• Gaston’s Tavern: Holiday Tree Cupcake
• Main Street Bakery: Frozen Snowflake Cupcake, Peppermint Cupcake, Holiday Cookies
• Sleepy Hollow: Pumpkin Waffle Sundae
Throwing a 3yo into the mix on top of all that and I would be making difficult choices at that point. I would choose one OR the other, not both. Do BOG if that's important to you but then decide to skip those characters, maybe go for some of the less popular ones later on if you want. OR skip BOG (you did it last time, right? So it's nothing new) and opt for making either Sandy Claws or Nick & Judy your priority and line up for that one first. Anticipate that you will only be able to do one or the other and be happily surprised if it works out to do both character greets. Just my 2 cents. I've never been to a party yet, but I've been reading the MNSSHP threads and trip reports with great interest and most people, especially those with young children, seem to have tough choices to make in order to get the most out of their party time, which includes ENJOYING it. 
