answer

as you say, it is a dream. just a dream, nothing special will happen after.

if want to have dream, you can only get it once a year during the New Year's Eve night.

go to sleep after 9pm game time then you might, MIGHT i say have a dream.
even if you have dream, its only ONE dream you can get that night.
well, unless you save before you sleep and restart them if you didn't get any dream or
want to see all of the dreams XD like i did.

if you go to sleep on that night after 9pm means you'll miss the festival.

there is 3 kinds of dreams:

there's some scene where everyone is dead_killed by karen i think_then you'll be at the
beach fighting karen. may is there. you'll see when you get it...

another one about the spirits combine with the cooking festival judge_forget what his
name_ become one something like that...

last is the scene where you're at the church in wedding gown with the MAYOR, Thomas in the
tux >. <

i don't know if there is anymore dreams.
i only saw those three.

all of the dreams are pretty weird > .