If you are putting lens flares in a “painting,” then think about the logic behind it. It’s a “painting,” not a photograph taken by a camera with a lens, which is what causes “lens flares” in the first place. Why would you put an effect that’s caused by the mechanical design of a camera system in a painting? It makes far more sense if you put it in a photograph or video instead of a painting. And if you are trying to emulate how photos and videos look with a painting, then think about why you’d want to do that and how does it actually benefit your painting. What extra merit does it actually add to the artwork? That is why I say they look odd in paintings–the logic just doesn’t work.
The re-posted first image looks good. I like the juxtaposition of the little kid in red and the large structure in the background.
The main issue I see is with the composition. You have these trees lining the two sides of the image, and I know you were trying to use them as framing devices in the composition, but the way you did it doesn’t work. They aren’t integrated into the overall composition enough, and makes it look like you cropped what should have been a more square image too narrow vertically. I suggest experimenting with a different aspect ratio and shifting some stuff around so there’s a better sense of integration of the trees.