Welcome to Subeta, ! With regards to your question on overlays, this Rule Center entry may help to clear up any confusion.

Nothing happens if your pet gets hungry or unhappy, except that a hungry pet cannot fight in the Battle Coliseum. :)

We do have a lot of currencies. Check out your currencies page to see them all, and how much you've got!

As for what's fun, I would definitely recommend getting in on the Morostide activities (trick-or-treating, the avatar Zapper, the Pumpkin Patch) while you still can. It's one of the best holidays of the year, and you'll get lots of cool stuff for you avatar, among other things!

Welcome to Subeta! I see your questions have already been answered, but if you have any other queries, feel free to ask c:

Useful Links:

What to do on Subeta? Useful general information for newbies Finding friends (Chit Chat) SubetaLodge (Offsite item database, pet colours etc.)
FAQ Site Event: Morostide (FAQ)