I just asked Peter that question and he responded yesterday, on a Holiday no less. He does make a Current Mode version of the Hyperion but he prefers the Voltage Mode version. When I had the Voice I was using an AR phono stage. My Seta L Plus has both TI and Voltage operation, switchable on the front panel. The loading switches for Voltage Mode are on the back panel.
You sure can. The coils and magnets are identical. A rebuild replaces everything that moves. I do not think there will be much of a change. The Hyperion already has an excellent stylus. The micro ridge stylus might track very high frequencies better, but we can't hear that high.