A couple of really nice images and very different from one another .
In the first shot you have handled the exposure well with no loss of detail in the high lights or shadows and that smile is to die for , well done on a beautiful portrait and I really like the B&W conversion it works so well with this shot . The only down side that I can see is the focus , it looks like you used quite a wide aperture which gives you a very narrow depth of field and make it rather easy to miss your focal point , in portrait photography the eyes are everything but in this shot the eyes are a bit soft where the hair at the top of the image looks like the sharpest point , a few millimetres further in and the eyes and that smile would be pin sharp and you would have an absolutely cracking shot on your hands ,
I can see why you like the second shot so much , it's a great capture and in this case the narrow DOF helps to make your daughter stand out against the background , that along with the vivid colours and lovely pose make for a beautiful image . The only thing that I would change is the crop , I think there is just a bit too much space behind her and I would try cropping in to the back of the boys head to clean up that area and balance up the image a bit more .