Get rid of the Mutamix since you have two u4xVCAs and replace it with the Happy Nerding PanMix. Now you have a stereo mixer with a headphone out built in. You can get rid of the Intellijel Headphone Out and the blank panel and pop in another Intellijel buffered mult or the Intellijel ZeroScope.
Also, you're 1HP over on your bottom row.