Current flows in the same direction (or CCW) for both circuit A and B. In respect to ground, circuit B is just a rotation of circuit A along the same path - these two circuits (A and B) should be entirely identical, regardless of the rotation positions of these elements. Why is there a change of sign in voltage (i.e. +12V for B and -12V for A)?
Circuit C is a flip of circuit A. Current in A and C flows in the opposite direction - CCW for A, and CW for C. Their signs of voltage should flip as well. Why is that is the simulation I get the same voltage sign (-12V) for both nodes (A and C)?
Why is there a change of sign in voltage (i.e. +12V for B and -12V for A)?
Not quite. What you should get when you rotated the circuit was this: -
And now, both nodes will have the same polarity voltage.
So, if you actually did reposition the GND node to where you show it in your original picture, the voltage polarity would reverse. But that ain't a simple rotation!