Hi G.,
Both are very easy to qualify for. As long as she is not working, she'll qualify for the pregnant medicaid and even if she is working, she will most likely qualify. My husband was working when I got pregnant yet I was not and I still qualified. As far as WIC, all she'll have to do is show them a medicaid card and she qualifies.
The baby will be covered the first year after being born under medicaid insurance. If she starts working then she can reapply after a year and either qualify for medicaid or CHIPS. It's usually very hard to get ahold of anyone via phone at the Health and Human Services office. My advice would be to call 211 and they can provide you more information and mail your niece an application for assistance.
Good luck to you and your niece.