Hi Sharon,
Thanks so much for stopping by the Moms Panel to ask your question. What a fun grandmother you must be to plan such a magical vacation for your grandchildren! I'm sure they are going to have a spectacular time at Walt Disney World.
Rest assured that your 2 year old grandchild will have an amazing time within the parks. Disney Parks actually released a great resource for parents (and grandparents) with little ones. Our family used this resource during our last vacation for our 3 year old princess, and she ended up having such a memorable time. You can check out the page here:
Planning for Preschool Kids and Little Ones.
As for announcements of theme park tickets, Disney dining plans, and Walt Disney Resort special offers, there aren't any set dates. Most guests have noticed a trend of special offer announcements being released about 3 to 6 months out. For example, if you are searching for special offers for spring, you might see an announcement on the Walt Disney World website and social media channels sometime in the fall. Again, this isn't guaranteed.
I hope this answered your question, Sharon. Please feel free to ask us any other questions you may have while planning your magical vacation. We're always here to help.