These are all great initial questions to answer as they'll better steer you towards a certain product and financing terms.  

I can recommend shecky who chimed in above with hrre, they run a tight turnkey ship with a good retail product in indy.

And I did find the meter I have, I think I paid $199 for it on Amazon. https://www.towerclimber.com/product/trifield-100xe-emf-meter-2/If it's a great deal, I'd check it with the meter at different times of the day.

If she is realizing that she cannot physically do the stairs and they are structurally sound, then offer to let her out of her lease, but if the stairs are truly unsafe then FIX THEM! 

There are great conventional loan products that have the similar down payment requirements but could be more advantageous cause it will not require a refinance to get rid of mortgage insurance.  

Find out what you qualify for and what product nuances they have and then you'll know. 

I know it says you need a physical address but would that count?

You could have the coolest neatest product but if it’s in a bad location it will greatly affect the value in the demand.

Then you can either refinance it into a long term financing product or sell the property for profit.

In addition, you will have a lot of trouble getting a great deal with an loan FHA product so I would recommend speaking to a lender about using a conventional loan product.