The deck that Ocean and Angelique are being held hostage on by Black Mask's gang is the infamous McBarge formerly a floating McDonald's that was left abandoned after 1986 in-universe.
As "Circe", Kate uses a pair of karambits; in the comics, she does own several such knives, though has never been shown using them.
This is different to the location shown on Cisco's map, which showed the city as being on the west of Lake Michigan.
While using her night vision, Batwoman's coordinates were shown as being 42° 5' 23" N, -75° 6' 13" E, placing Gotham in the real-world location of Delaware County, New York, on the north of the Pepacton Reservoir.
A fire at Arkham Asylum is mentioned, there was a fire shown there in season one's A Secret Kept from All the Rest (2020).