I agree re the credit scores. It is best to work with a good mortgage broker. I have had clients in the past with credit scores in the 500's and they worked with the client to get the credit scores where they needed to be . Sometimes it is little things you can do to get the scores up.
As to no downpayent, the best loan is a Rural Development loan. This is a government loan with no downpayent. Baton Rouge and Baker are not included, but all surrounding areas are. Central, Zachary, and all in between.
Hope this helps and good luck!