Painting a texture on a height mapped mountain using PS and Blender Paint

Hello everyone,

I am in a little bit of a crisis. I have a mountain island terrain that is jutting out of the water. The top surface is flat, but I will be adding mountains and cliff edges on top.

I am tasked, for my group, with painting the textures on the terrain itself and am having the following two issues:

  1. How to properly UV unwrap the height map. I tried a few different ways but none are good enough to work adequately in PS, where I can do my best coloring work. As a result, I have to live paint on the object itself in Blender, which leads me to my next problem.

  2. I can get an ok result in Blender paint, but i notice once I remove the world lamp, the coloring and object look awful. Is it worthwhile to worry about how this object looks without the lamp? I ask, because I must send this object to Unity in a few days and I don’t want it to look like it was colored so badly.

Thanks, here is a photo of what I have so far: