Fannie Mae dangerous condition negotiating?

[Casey Beaulieu]

Looking at a property offered by Re/Max Advantage, stated in the ad that it is a Fannie Mae property.

I did a quick recon since its in my area.  The home has noticeable mold, damp (at least) carpet, and then normal foreclosure issues (builders grade fixtures, built in 87 and never updated).  Black mold on walls, some noticeable water warped walls.  

I did a quick search, and saw that if its "dangerous" you can negotiate to have these items fixed at owners expense (if its considered to be something that would have to be done before the next buyer). I think these issues are keeping buyers away, possibly not knowing that a fix could be negotiated into price.

Few questions:

Can this negotiation only be done while under contract?

Will Fannie Mae only fix then sell, or will they just get a quote, and negotiate that from the price? 

Is there a better way to go about it than having a mold remediation company provide a quote, and giving that to the real estate agent? 

Has anyone had a similar experience? I'm wondering how frustrating it would be trying to get this to work.

This home would "work" for me if I can get away with flooring/paint/regular renovation stuff but mold (for the price) isnt worth it.