Okay, what was your goal with these photos? Are they photos of your children? Are you trying to achieve children's portraiture kind of photos? The critique would depend a lot on what your objective was.
As just snapshots/record shots of your kids I think these are really cute.
If you are trying to go for a more professional look, these are the things that I notice without putting too much thought in it (I critique substantially because that is what I like for my photos and that is how I learn, so please ignore it if you want)
In the first I think your focus fell on the basketball post behind them, hence the reason they are not in focus. It is a cute snapshot, though and I like your black and white conversion in that one.
The second one is hard to say but once again I think the focus might be behind the baby... also she/he gets lost in the busy-ness of the background! Once again it is really a cute photo for your personal album.
Third one could be okay with a bit of cropping, right now it is too centred... I find that rules of 1/3rd are the most important thing after getting exposure and focus spot on. The shadow is also distracting to me! Shooting in full sun is a skill that takes lot of practice! Try shooting in open shade (but not dappled)
In terms of catching the moment, expressions etc, I like the last one the best! I can't help but smile with them!
Also just wanted to mention that I personally dislike selective colouring that doesn't tell a story and is very gentle (that would be 99.9% of all selective colouring)... look at your photo: What does selective colouring really add to it? Is it to make your subject the "topic" of the photo rather than the background? In that case you need to find a background that isn't distracting? Is it because it gives the old fashioned gentle hand tinted in the darkroom feel? Not in this case...