How to Show the Total Word Count of an Entry? Any way to show the total word count in real-time to authors while they are writing an entry that has multiple blocks? 

I don't need per-block word count ... I need total word count shown in real-time.
You'll need to add a plugin like this one from Lindsey DiLoreto that allows you to insert your own javascript into the CP.  Then you'll need to write some javascript that counts up each word in a textarea input for each block.  I'm sure stackoverflow has several answers on how to do that.  Keep in mind Craft already has jQuery installed if you choose to use it.