With the following little script you can do that.

Code

function mySQL(ref, dates) {
  var output = [];
  for(var i = 0, iLen = ref.length; i < iLen; i++) {
    var user = ref[i][0], begin = new Date(ref[i][1]), end = new Date(ref[i][2]);
    for(var j = 0, jLen = dates.length; j < jLen; j++) {
      var date = new Date(dates[j]);
      if(date >= begin && date <= end) {
        output.push([date, user]);
      }
    }
  }
  return output;  
}

Screenshot

data

outcome

Example

I've added the script to your example file.

If by "add data labels for each data point" you mean "adding labels from A column to each individual point" - then that is not possible. you can add only values as a label for each data point.

As for "two independent axis" - this can be easily achieved by adding new series from another column. All the above would look like:

From there you can add trendlines or customize each individual data point by changing color, size and shape:

If you will re-shape your table a bit you could do this:

Of course, if you really want so you could add custom label per each data point manually by inserting a drawing:

demo sheets: one, two