Greetings Sarah!
Welcome to the Disney Parks Moms Panel. I think it's just wonderful you are already planning your 2020 vacation. So many new and exciting things will be happening at the Disneyland Resort by that time. You'll be able to play along Pixar Pier in Disney California Adventure Park and explore
Star Wars: Galaxy's Edge in Disneyland Park.
The Disneyland Resort is a great destination for large groups. With parks, hotels, and the Downtown Disney District in such close proximity, it's very convenient for your family to split up throughout the day and join back together as often as you'd like.
Group Discounts are available if your party will be occupying at least 10 resort hotel rooms, which doesn't sound like it will apply.
Disneyland Resort does currently offer
Military Discounts to active duty and retired service members for park tickets, hotel rooms, and Disney PhotoPass. These discounts are announced on a year to year basis and not always guaranteed. I would keep checking the
Special Offers and Discounts page on the Disneyland website as your travel date approaches as well as contact your local military base ticket office to check for these discounts. Currently these specially priced military tickets can only be purchased on base and are capped at 6 tickets a year. Exceptions will be made to this amount if you have more than 6 members in your immediate family, but it will not be extended to other relatives or friends.
I hope this helps, and please stop by as you plan more details of your magical vacation!
-Jennifer