Great ideas, most beautiful horses and a great humor in the boy with plane render
May I make some suggestions?
In the stampede render I feel as if the brightness of grass and the stones in the forground do not work so perfect together. Could you try more bright and raw rocks with less displacement? And/or reduce the luminosity of the grass especially in the forground?
If you place the sun so that the model plane throws a shadow on the boy than it could work a bit better. I guess it must be a model plane in the foreground. otherwise the position and direction of the boy would not work together with the plane, right?
...only my thoughts...