Brad, I have to confess that I'm starting to get confused too by all those different available rims.
Yes, the 10J are approved for the rear axle only. I suppose they have the same offset as the 9J with 17 mm spacers.
Porsche claims more "traction" for the 10J wheels on the rear axle, interesting.

Can't say much about the new SportTechno rims which are needed for the powerkit, the information I have is very very limited. Again surprising because it seems that the US got more information regarding the powerkit/rim issue than Germany.