What is the Outline/Border best practices for performance?

I am wanting to integrate a ‘outline / border’ system into my UE4 project. Where when you are interacting with a mesh that it adds a ‘white border’ around the item.

From my research and testing I have seen 3 methods used. Now I am very curious on what the ‘Best Performance’ for performance fps and multiplayer.

Method 1 : Post process border: A method like this marketplace item: which uses a post process volume to turn on/off the outline.

Method 2 : Have another static mesh with a material that turns on/off with interaction. Like in the tutorial:

Method 3 : Have the original material on the object have a ‘border param’ and when you overlap the interaction box you make the border param visible.

Now I am wondering as far as Performance/FPS and any multiplayer related issues that might happen. What is the recommended method to add outlines / borders as it relates to performance?

Thanks in advance