Top down 3D game environment workflow

Hi, what is the recommended workflow for making 3D third person top-down game environment such as the caves and cities in games like Diablo 3?

Quick isometric sketch in procreate --> Grey box concept 3D in Unity3D --> Screenshot of grey box environment from desired angle (what angles are used in Diablo 3?) --> drawing detailed isometric art in Procreate on top of grey box screenshot layer --> 3D sculpting building blocks and elements on top of 2D detailed drawing layer from Procreate in Blender --> importing 3D building blocks in Unity from Blender (with or without animations and effects such as lightning? --> Adding lightning effects and animations in Unity, scripting etc?

Thanks!