The same as you would for summer.
Use outdoor fabric- the same way you would for Summer. But you'll probably want to be sure they're under cover so they don't get waterlogged & moldy.
Yes they should... I usually shop at Joann fabrics and they definitely have an aisle of outdoor fabrics. At my store it's near the upholstery fabric.
Hi Mary, here's a great no-sew tutorial to make outdoor pillows - https://www.hgtv.com/design/make-and-celebrate/handmade/easy-no-sew-outdoor-pillow-covers. Depending on where you stay you'll need to pick a fabric that will withstand whatever mother nature decides to throw at them. Your fabric shop will be able to guide you. Have fun
You're most welcome Mary and using a festive tablecloth from the Dollar Store sounds like a great idea.