The low credit score is not what would be my first concern. I know of 2 people close to me that had terrible scores a few years ago, one was a recently divorced single mom with 2 young kids (most bills were joint with ex husband, who hid the bills and didn't pay them), and the other was trying to put herself through school for 1 year with 3 part time jobs and lapsed on the non-essential bills. They both have paid everything perfectly on time since that time, but it took about 3 years for their scores to go from the 500s (or less) to the low 700's now.
My bigger concern would be the income - a recently opened bar? 3/4 of restaurants fail within a few years of opening - how good is business at the bar? Assuming business from the bar is good and it's not in danger of closing, what percentage of her income comes from that job? As for the property management job - how likely is it she will keep that job when she moves out? Not only that, but her current rent is about $200 less that her new rent would be, plus she gets a sizable discount I imagine. If she's paying all her bills now, that's great, but if you take her, her expenses will jump significantly, and is she in a good position to be able to handle the extra expenses?