Your filter supply line configuration is used in a commercial sump design to keep the sump quiet and reduce air bubbles. I like it and would keep it. It also makes the sock filters very easy to access and change!!!! Easy maintence is tops on my design list!!!
The coarse sponges seem to not be needed. They should catch some large debris from the plant and fish compartments... but I would just let the pump push this back into the aquarium then be filtered out when the debris hits the sock filter.
I might consider making the whole configuration one long linear chain instead of the two sided design you have currently. One long filtering chain instead of two filtering chains meeting in the middle seems like a more efficient design to me.