I am assuming your skimmer is located near you overflow output and that the bioballs are closer to the return side of the sump. Am I correct?
If you are set you up so that your water is running through the bio ball section just before hitting the return, then yes, ditch the bioballs and you might consider using the bioball section to hold a couple of media bags of carbon in there instead... this way, you have carbon filtration without having to hook up a seperate reactor or canister filter.
If you had a larger capacity skimmer I's say skip the fuge but I think you will be fine with it in the center section in your case.