DRV8825 EVM Board Layout Query

Hi,

I am reviewing the gerber files of the DRV8825 EVM and have the following questions:

1. The Kelvin and GND layers - are these connected?  Why this arrangement rather than a GND / KELVIN layer and a power layer?

2. The bottom right corner - are these vias stitching together the top and kelvin layers primarily for better thermals?  

Evan