Temporary Religious Worker visa--any experience?

Anyone have any experience with the Temporary Religious Worker visa? We're thinking of creating a position at our church that would be like a 2-year internship. I know that salary requirements are different for religious workers, but I can't find any specific info on the Temporary worker requirements. My main questions are this:

1) Can a Temporary Religious Worker be part-time?
2) If they can, how are salary requirements established for that?
3) We are looking at providing free accomodation for the intern. Can the value of that be factored into the salary package?
4) If we find someone we really like, can they extend their Temporary Religious Worker visa beyond the initial 24 months? Or can they be substituted with a Permanent visa?

Thanks in advance for any help you can provide!