I would never lay fabric directly on the shelves---protect them from the finish.
If it has been in a smoking home, you can set vinegar in shallow bowls on the shelves for two days, and most smoke will be gone....
If you want "doors", just put some velcro tape above the shelves, then on fabric, and hide with curtains--or use spring rods if that will work...
Have fun!
I am de-stashing right now--need to get back at it!