1) I don't know how to get the poser pro to use the poser 7 runtime.  

You just add the p7 runtime as an additional runtime, just like you did with poser 5,6,and 7.

2) Poser pro is rendering slower than Poser 7.

You weren't using the 64 bit background render engine you should have been using.

3) Poser pro background renderer just sits there with cpu 0% for fffrender64.exe

Sounds like a bad install to me, or possibly not applying the recent sr1 patch.

I'd uninstall, and then reinstall, apply the sr1 patch, and then retry your test.
 

Way too many people take way too many things way too seriously.