Can this be tagged as an Animal Crossing reference due to the pose?
Nah, the pose looks close but cirno's not done in animal crossing's "style" and the item isn't something from animal crossing like the leaf or bells. Might be a coincidence.
Yeah, I'm with NeerHeer on this one- this is just Cirno showing off a new buggy buddy she's found; for me, it'd be an AC reference if we were viewing her from a somewhat isometric perspective.
