Hi Daniel,
The cooler slot could work. One thing to keep in mind as you plan your project is weight distribution throughout the boat, i.e. gas, batteries, driver, live well water, cooler, seating, anchor, tackle, etc. Start with the current unmovable items, batteries, gas, driver, then offset new items to keep the boat balanced; otherwise the boat may want to steer in one direction better than the other.
Look at your plan; if the gas, batteries and driver balance each other out (and they should); you'll through yourself off balance when you fill the forward live-well, so you would need to offset that in some way.
Do you have a layout of what is under the seating and deck?