Do Exposed Pads need to be connected to either + V or -V?
Can I connect to the ground?
The ADA4927 data sheet states that the Exposed Paddle can be connected to any plane between and including the +Vs and -Vs.
You can connect the Exposed Paddle to +Vs, -Vs, or GND since your GND is between your +Vs and -Vs.
In addition, the Exposed Paddle has no internal connection and can be used for heat dissipation as discussed on page 7 of the DS.
Thanks and regards.