I was going to go with house B too in the sense that while the walk out is great by the time it snows a lot in the winter you will have to walk around to dig out anyways in order to use the door potentially in the other house.

Having two daycare place options in house B means you can move in and start daycare right away in a room you can close up at the end of the day and you will have access to your whole house all day too as compared to being in the basement. Then if you do finish the basement you can think about other uses such as making it just for gross motor with room for games and active play or a smaller area for the daycare and more area for other family needs.