Neither is a bad choice.
The AKV villas that will be finished by that time are all those (5th and 6th floors) that will be in the current AKL building. Thus, for June you will essentially be staying in AKL if you can get a reservation. AKL gives you animals to view, good eating places, an excellent and large pool and play area. You bus to all parks. It would be fine choice for kids that age.
Contemporary gives you something you may consider more important: MK right at your doorstep (you can walk over) which, with 4 and 7 year olds, may be the park most often hit in any stay. It also has good eating places and a decent pool. Downside is its stark look inside (and from outside) the building (although rooms are nice).
Personally, I would do AKV but that is because I really do not like the look of the Contemporary either from the outside or when inside. Others think it is fine.