I used bounds to calculate actor extension for an internal project.
I a partial solution.
Like you said you may have some error when you have many component inside and will highlight things you may now want.
My recommendation is to use a component just a box component for draw the frame you want.
If you are concern about the physics for some objects. I would recommend to use the a custom component (child from box). And update the location each time for second instead of each tick and disable if the velocity of the object is to fast.