Heya, these sprites kick butt! Well drawn, but my favorite thing is the perspective you chose, and it looks like you nailed it. I'm not worried about the grounding issue. A quick shadow always solves that. You just hadn't done it yet. Though, a combo of drawing order organized leaves drawn in front of the human sprites as they walk around and a shadow would be great. IF you're using alpha that is. 50/50 dither and solid shadows usually aren't so hot. Something else contributing to the problem may be difference the grass and human sprite colors. Grass is a bit on the bright/neon side in comparison.
Is there a future planned for this, or is it just random stuff?