You are a brave man. I am just beginning my Leica experience as well. I invite you to participate in my Learning Leica M thread. I am sure we can learn from each other's adventures with Leica Range Finders.
That being said, I don't hold myself out as an expert by any stretch. So, read my thoughts below with that in mind.
If the EXIF data shown with your images is correct, you were shooting at very wide open apertures. This has two effects. It makes getting critical focus very very difficult, and probably is unrealistic with moving subjects like a child. Second, lenses are less sharp at these apertures, often giving a dreamy appearance to the image. The dual personalities of many lenses is a wonderful thing. Dreamy wide open, extremely sharp stopped down a couple of stops.
The next thing I noticed is that you were shooting at ISO 400. One thing I am finding in my M10 experiment is that with the sensor in that camera you can shoot at much higher ISOs and still get very high IQ. That enables you to shoot stopped down a bit even in lower light.
On technique I have found in situations similar to what I see in these images is to set the drive mode to one of the continuous modes, focus with the Range Finder, the rock ever so slightly back and forth while taking multiple shots. This can compensate for the very shallow depth of field. You can the pick the best out of the batch.
That is a beautiful child. You are a fortunate Father. Enjoy every moment.
You have to admit that the Leica colors and rendering are beautiful in those images. One of the things that make Leica cameras special. To heck with the critical focus. The images are beautiful. You will love these pictures the rest of your life.
