Today was "Halloween at the Aquarium" and they had a meet and greet with Tom Nook and Isabelle, so I got some pictures with them!
They also had an Animal Crossing backdrop for taking photos (I'm dressed as Redd, my sister is Tom Nook, my friend is in the Froggy hat, I've covered her face for privacy.)
Some scuba divers carved pumpkins underwater, one of which was wearing a froggy hat! (it fell apart a lil bit, but still cute!)
Throughout the rest of the aquarium there were signs with Blathers' descriptions from the games. They also seem to have their own Resident rep for the aquarium sharing additional facts.
Additionally there was a stamp rally just like in New Horizons. There were 4 cardboard standees of Animal Crossing characters to find that were by little booths with candy buckets to trick or treat from, and a person to stamp your card.
I got a free reusable bag for getting all of the stamps.
The gift shop had this display of animal crossing plushies, they were a bit pricey though, ($40 for Flick/Gulliver and $25 for a small Tom Nook, Isabelle, or Blathers' head) I've actually seen these same ones at GameStop and Target in my area so I didn't leave with any of them.