Some of us have recovered the headliners. The headliner board was reused.
The material is available at automotive trim shops, automotive stores under the name "Heads Up", fabric stores like Hancock fabrics and online. I mannaged to remove the headliner by myself but man I wish I had someont to help. The areas under the rear passenger'* grab handles were damaged during removal. I fixed the areas using duct tape prior to recovering and it came out OK.
You will need to bend it slightly to get it out but not enough to put a crease in it.