In both cases, light sets were placed about 12 o'clock position, IBL slightly to the left, Infinite slightly to the right.  Initial IBL test was rendered to at 15% intensity; Infinite rendered at 75% intensity.  I did increase IBL to 100% on the second example which intensified the illumination.  Again, this was only performed with white, non-image light set.  If your friend is using an image in his IBL to light the room, you should be using the same light source image for your renders.  One IBL is enough to provide your ambient lighting needs, more will saturate the scene.  Also, position the IBL close to your infinite light for a more exacting directional illumination.

The extra node for the Ground Plane zone is not connected to anything and is irrelevent.