Evaporation always occurs at the lowest point of a system (return pump area). If the return is baffled off into a small area the evaporation rate may lead to the pump running dry. A reliable ATO and decent sized FW resovoir can combat this. Main issue would be leaving the tank for extended periods. My tank evaporates about a gallon per day in the winter time and that looks to be about what the volume of that cube.
If you extend the return to the water inlet area you would need a "T" off of the reurn line to feed the LR/fuge/skimmer area otherwise that area would not get any water.
If you extend the return to the water inlet area you would need a "T" off of the reurn line to feed the LR/fuge/skimmer area otherwise that area would not get any water.