How to handle Maternity Leave

[twinpossible]

Background: I am a Professor at a university, I teach American Sign Language. People in my profession with the right amount of education are very rare. I am supposed to line up a sub for when I go on maternity leave. I found someone that is a former student of mine and has the qualifications. My work keeps changing the requirements for my sub to apply. This has caused me a TON of stress. I have to keep going back to the gal I want to hire and ask her for more information or paperwork. They got my co-workers involved and now they ALL need to approve of MY sub. They are demanding an interview with her with only DAYS notice and she lives 9 hours away. This all just seems mismashed and not legal at all. It is hard to find any rules or regulations on this matter and I am about to loose it and bite someone's head off. Does anyone have any advice on how to handle this situation?