RE: FMLA and Job Interview
If other internal candidates are being interviewed, she should go through the same routine. If, however, she might be able to show later that you dismissed her candidacy and could have easily evaluated her application/resume, knowledge of her work, or other company documents, as you might have, or easily COULD have done with others, you could have an FMLA retaliation or unfair treatment charge looming.
I also would point out that she does not have any claim of a property right to a job she might apply for but not be able to occupy, like she does the job she left to go on FMLA. In other words, I would not hesitate to go ahead and fill the position, nothwitstanding her immediate non-availability for it. If it turns out she's the best candidate for the job, I'd simply use business judgement in deciding if I could wait for her to get back to fill it or if I needed to move on down the candidate list.