No, actually, the interviewer will ask you some questions. They will be very basic. It will be something like "Why did you quit your job?" and "When did you quit your job?" and "What steps did you try to take to resolve this situation before quitting your job?" It might help to report to them, chapter and verse, the laws you have found here regarding returning to work after maternity leave, using FMLA and that other thing, PDL, just to get it into the discussion.
It would be awfully good too, if you answer the question "Are you able and available and ready to accept another job?" in the affirmative, and "Are there any days, hours or shifts you are not willing to work? (Reason?)" as if you're willing to work anytime, any place, any hours."
The decision will be made not on the phone when you file by an interviewer, but by an ajudicator, after a few weeks, and after both you and the employer have given statements regarding the situation. After the initial decision is issued, if you are denied benefits, you can appeal and have a hearing. If the claim is approved, the employer can appeal and you'll be notified of a hearing date so a second decision can be made.
Actually, based on what you said, it sounds more like they changed your hours to accomodate the client they wanted you to take over, not as punishment for you because you'd been on leave, but to accomodate this client. Employers are fully allowed to do this. Did you discuss this situation fully with your employer, try to get this worked out, perhaps postponed for a few weeks until you could get other arrangements made?