Rhett,
This confusion is why I was hesitant about adding the "all" to the unique value list when you asked for it. So what I ended up doing is when I see the all chosen in the unique value dropdown I just do a 1=1 query (basically giving you everything as that is what all unique values would be).
As far as the uniquevalsfromfield adding a blank I had this fixed at one point them made some more code changes to account for a possible empty string value being in the data and I broke it again. But I now have it fixed again. Please re-download the widget.
BTW Version 3.0.14f is now available with the fix for the first query layer having multiple uniquevalsfromfields