Possible, yes, but will it be performant enough for VR? Probably not. The landscape components aren’t great for VR, but you can export them as static meshes and reimport them to get a few frames back, but with this method you should split it up into smaller meshes and use highly reduced LOD meshes to claw back some more frames.
Im sorry, but Im not quite sure what you mean by world scale. An objects scale just represents its relative size in relation to the size of the object at creation. A scale of 1.0 basically translates to 1:1 or 100% the size of the default or imported size of the object. There’s an option in World Settings under the VR header called ‘World to Meters’, which manipulates the default world size in relation to the HMD. By defualt its set to 100, which means 1u (unreal unit) equals 1cm of real-world distance.