Hello, the title may be really bad and the question may have been answered in the past but a clear yes or no will do. Is there a parameter definition in the TerrainLighting material to set the whole color to a blue(exemple) color or white ( equal to no color modification)?
If no would it be a simple to do a copy of the shader and to add a “Color” param with a mix at the end do the job of mixing the color?
To answer the second part of your question - by asking that question alone I would guess that your knowledge of shaders is still in its infancy - however - you are really going to need to learn them eventually - and using a color instead of a texture is probably one of the easier ways to ease yourself into tinkering about.
You could get around this problem in many ways - using a single pixel texture with the color, using an atlas and choosing the texture like that, etc… All of them will be wrong. I would not recommend trying to avoid shader programming. It looks scary but it really isnt - though just like any language - can get very technical and be very powerful.
Take a look at the unshaded material. Ignore lighting in the beginning until it starts to click. The minute you start bringing normal maps and lights into the equation it becomes… .bloated and confusing.