There are some that say BCV's pool may not be ideal for younger children (so big, very hard to keep track of) and in January, you may not get pool time (weather related, what's your min temp needed to go to the pool? and/or that is the time of the year for pool rehab), so I would not choose a resort only on pools.
Location wise, BCV does offer a bunch of dining options and very close to EPCOT and DHS.
BLT offers a lot in nearby restaurants on the monorail loop and MK. It is really personal preference which restaurants you think are better between BCV and BLT.
Personally, I would place a really strong suggestion on AKV savannah view. It is truely a one of a kind experience (where else in America can you stay in an African themed resort with views of actual savannah animals?) If the kids like the animals, then room time becomes it's own attraction, and an amazing vacation experience. The AKV Kidani pool area should be ideal for that age (if you have pool time). The Jambo pool slide will be fine for the 5 y/o but possible tame for the 8y/o.
Restaurant wise, you are more limited at AKV. There is no breakfast at Kidani, and no true counter service. Personally I'm very happy with the Jambo dining options, but you would want to bus to parks or drive a car for more dining options..