I'm not exactly sure what you are implying in your post. The children were probably going out perhaps to the Horniman where they often have morning events for local children. is that what you mean when you say ' the garden nearby'? You do give the impression that they are all tied up to a garden fence all day or something of that ilk. The fact that the weather may have been terrible is irrelevant. Unless there was a snowstorm or a child is ill,it is perfectly acceptable for children to go out in all weathers if suitably dressed. My children do and have done so from an early age. Children do so all the time, when their parents are taking older children to and from school at fixed times, etc. Flexi time isn;t really an option for school age children. At most nurseries and childminders I have used they do the same which is why spare changes of clothes are usually requested as are spare indoor shoes to change into.
I would imagine that at 5pm, the children were actually going home? Crying and coughing is also not that unusual. I live on a popular walking route to two local schools. There is considerable ' child noise' at certain times, including tantrums, tears and whatever, but that is surely life? I doubt whether it has an as you call it, an 'emotional impact' on the neighbourhood.

As I said before, material planning impact of any decision is something everyone has a right to raise, but some of the issues raised by local residents in this area are coming across as more than a little strange.