Landscape Isometric View Visualization

hi everyone,
I am a landscape architect working on park projects, and trying to use Blender for texturing and render (by Cycle). Attached images are the result, and hope someone could give comments, or suggestions to improve them. In general, I hope to get diagrammatic style, clean, not super photo realistic, like physical model.
This is the first time using Blender to do this, and I also found some obstacles, and hope some people give advice.

  1. library is a big issue, like trees are very hard to find, as well as textured people.
  2. lighting effect is hard, I just use one “sun”, it looks ok in these Axons, but at human eye level, it is really bad! I tried HDRI sky, but cannot make it work well…
  3. the file conversion workflow is converting rhino to OBJ, then load in Blender. But every time I made modification in Rhino, I have to re-import again. I wonder whether there is an easier way to doing this, or how people bridge Rhino and blender.

Thank you!!