Yes, plastic is not the best for long term storage, however if it's just for a month till the bazaar, you will probably be fine. As far as wrinkles go, if you have a spare bed, laying them flat is the best. YOu can put a sheet over them to keep the kitty off. Another way to minimize wrinkling is to fold them on the bias:
http://annfahl.blogspot.com/2012/02/...re-quilts.html