The Kamakura shops were snow bunny shaped igloos with snow Miku themed merch such as: a glowstick, a lantern, pair of gloves, clock, snowglobe, Yukine airplane, muffler, Miku twintails, Rin ribbons and Luka headphones.
Second igloo had some instruments, but they were only for show, and seemingly for HoloModels. And some Miku and Megu virtual plushies. Third igloo housed a life-sized snowglobe and some ads for a snow photo festival in Sapporo.
The snowball fight field was a small set of cover walls, tree cut-outs and two sides with neon snowflakes for teams. The set didn't have any special function, the board pointed to the gloves you could buy in the shop, which allowed you to create and throw snowballs. So it was merely for a pretend snowball fight if you bought the goods. The bgm for this area was pretty much the White Luminescence album.