I think you have some really adorable expressions on the kids faces here. You can really see a lot of their personality!
I'm very new, but I'm trying to comment more, so here goes.
#1: Her eyes are so dark, her pupils get lost in them and really make them look flat. Perhaps some more effective catchlights could help or maybe just some dodging.
#2: I'm not crazy about the parent's hands in the photo, and the poor kids wrist got chopped right off. Also his eyes look oversharpened.
#3: Is my favorite. I think his expression is just so cute.
Your b&w conversions all seem to be really dark with a lot of gray in them. I did a play on the third, just lightened the shadows, adjusted the brightness a little, dodged his eyes and added the border. I think it could be improved even more, but I'm still learning. You didn't say if plays on your photos are ok and I'll take it down if you want me too.