I don’t know what it is called. How can I visualize electric cables or water pipelines on may map? For example in Cities Skylines you can switch your view to
electricity:
or water:
If you are using built-in render pipeline, you could go with Unity - Manual: Replacing shaders at runtime. Essentially, render the scene with custom shader, based on original material’s tags.
To set the building’ colors you could then use MaterialPropertyBlocks applied to the renderers. You could either work with color property, or specifically creating properties like ‘HasElectricity’ and just let the replacement shader read that value.
It depends on how you want to do it. If you want to do it by colouring the buildings you could make a List<> or Dictionary containing all of the ones on the grid, then use it to swap their material out for a colour that corresponds to ‘good’ or ‘bad’. Maybe have a range of colours that you replace using a Switch statement, depending on how good or bad it is.
Masking the area around a building would be something you do with a shader applied to the object that affects the ground around it. But be careful to exclude other buildings from it.