Be a bit more patient, I'm busy typing!
Well, open the block in Block Edit then select one of those polar parameters. Open the properties palette and it will show you the names of the distance and angle parameters of each.
Now you can get/set those the same way you do with the visibility parameter. E.g.
_$ (setq eo (vlax-ename->vla-object (entlast)) )
#<VLA-OBJECT IAcadBlockReference 000000003c393bd8>
_$ (dyget eo "1 Leader ON")
nil
_$
_$ (dyget eo "1 Leader")
nil
_$ (dyget eo "1 Leader ")
#<VLA-OBJECT IAcadDynamicBlockReferenceProperty 000000003c4e6638>
_$ (vla-get-value (dyget eo "1 Leader "))
#<variant 5 1470.23133612937>
_$ (vlax-get (dyget eo "1 Leader ") 'value)
1470.23
Note, do a normal List on the block to find out the "real" names of those. Here you can see the parameter is actually called "1 Leader " including the space.
Note though, the "coordinates" is not X,Y position from origin. It's polar, like in a radius line of a circle. So you'd need some trigonometry or using the angle and distance function to convert between Cartesian & polar coordinates. The polar (built in) function only converts from polar to xy, my guess is you want it the other way round. So:
The trig method becomes a bit more complex.