It's always in the details!
To create these large marbles, that would be lovely lining the path to your party place, simply fill balloons with colored water and set them in the freezer. The only thing that I would change would be to stick to one color to create a cohesive look.
Use your summer patio furniture as props! Cover it with snow, like the folding chair shown above, and hand a lantern from the seat or back. Then, place teapots full of steaming teal and carafes of delicious hot chocolate on the seat for a serving station!