It's not clear to a western audience if this is closer to Noah's Ark or closer to Santa in terms of "how literally do people interpret this event".

My question, as I know very little of Japanese folklore, was whether this is more like the Easter bunny (just a game) or the second coming of Christ (something people actually build their lives around).

Eh, good one :) (btw we don't, and I think the whole preschool parents will soon hate us but hey they're the ones lying!)