These are fish frozen in an ice sculptor. Susukino is about three blocks from Odori Park, where the real yuki matsuri is taking place. Susukino is where all the adults play, and Odori Park is where all the kids play. Hanging out in both areas is definitely doable. I recommend not using the subway, just walk and save money.
The real benefit for coming through Susukino would be the ramen stalls at night. Of course the light up go too, but Odori Park has best light up display. Susukino's illuminations stay on longer than Odori Park. I'm blogging this as if I am taking notes so forgive me for lack of narration.