Given the age of the kids, I would say AKL and suggest a Kidani savannah view. The kids will love the animals. You will get 3 full bathrooms. The pool area, and particularly the splash play area, are great for kids that age. The park buses stop at Kidani first, and are generally empty. That gives everyone a seat and makes boarding with a stroller a little easier.
BWV boardwalk view is one of our favorite rooms, but they are smaller and only have 2 full bathrooms. Also, the noise from the boardwalk can be a little much after 9PM, which may affect bedtime for the little ones (and the big ones in some cases!). The pool at BCV is awesome, but probably a little to much for a 1 and 3 year old. One advantage to either of those locations is easy access to Epcot and HS, but the buses to MK can be a bit of a pain.
Have a great trip!