Hi Sean,
Disney's Animal Kingdom Villas - Kidani Village is a beautiful resort. From the rich and amazing decor to the fantastic sight of exotic animals outside of nearly every window, it is amazing. Your toddler will likely enjoy the Uwanja Camp area of the Samawati Springs Pool. Uwanja Camp is an interactive water play area that is tons of fun for little ones.
A two-bedroom villa will certainly give you enough room for your party as it will sleep up to nine adults. Depending on the configuration of your traveling party, you also might be comfortable in a one-bedroom villa, which can sleep up to five adults. You can learn more about the
villa sizes and configurations at Disney's Animal Kingdom Villas - Kidani Village by clicking on the link I provided.
As for when to book your vacation, I always think that booking as soon as possible is a good idea. If you are booking the room using a traditional payment method such as credit card, you can do so as far as 499 days in advance, which means that for a travel date of May 2017, you can book now. You can do so by calling 407-W-DISNEY (407-934-7639).
If you are a Disney Vacation Club member and Disney's Animal Kingdom Villas - Kidani Village is your home resort, and you are looking to book using your vacation points, you can book up to 11 months ahead of time. This means that your booking window will open up in June 2016. If you are a Disney Vacation Club member looking to book this vacation using vacation points and this is not your home resort, you can book up to seven months ahead of time, which would be in October 2016. In either case, you can do so by calling Disney Vacation Club Member Services at 1-800-800-9800.
Please do let us know if you have any further questions, Sean!