I looked over the code. I think the problem you are having is that the feature gets added to the same graphics layer as the drawn graphic, so you will have a mix of drawn graphics and feature graphics. Your examining the drawn graphic, which has no attributes.
I would create a separate graphics layer, like
<esri:GraphicsLayer id="myParcelGraphicsLayer"/> in the map and then reference it at:
function onResult(featureSet:FeatureSet, token:Object = null):void
{
if (featureSet.features.length > 0)
{
for each (var myGraphic:Graphic in featureSet.features)
{
myParcelGraphicsLayer.add(myGraphic);
and in your AssignNeighborhood section.
It should work then.