You can if you want:

    var jp = function(last) {
        return formatNames2('John', 'Paul', last);
    };
    var je = function(last) {
        return formatNames2('James', 'Earl', last);
    };
    var lh = function(last) {
        return formatNames2('Lee', 'Harvey', last);
    };
    var c = function(middle, last) {
        return formatNames('Clarabelle', middle, last);
    };

But I find this cleaner:

    var jp = formatNames2('John', 'Paul'};
    var je = formatNames2('James', 'Earl'};
    var lh = formatNames2('Lee', 'Harvey'};
    var c = formatNames('Clarabelle'};