The real problem in the scenario that you describe is your credit score... 611 is a little too low for any legitimate lender (that I know of) to offer you a home loan. Especially with an FHA loan.
There are several lenders that will grant you a loan with a credit score as low as 620. However, your interest rate will be somewhat higher than average, and the closing costs you incur will be somewhat higher as well.
A minimum credit score of 640 is the score you want to shoot for. And, if you can get it to 700 or so, you will have no trouble finding a lender. Especially with a debt to income ratio of only 15%.
The good news is that, with a little bit of work and due dilignece, you should be able to raise your credit score to a more acceptable level in as little as 3 to 6 months.
Just pay all of your bills on time, and in full (if possible) every month.
And, if you only need to establish a credit history, a pre-paid (you deposit monry into an account for future spending) Visa or Mastercard. Shop around with you rlocal banks to find one with low costs.
I agree with Paul's answer that you would have to own the home outright probably before that would be possible and the lease with the option to purchase would probably be the best bet for now for you both. Definitely consult your attorney on these types of documents.... more