The cat actor who played the stray cat is named Lala.
If you go upstairs in the bar in The Slums, there's a bowl filled with liquid and what looks like RAM blocks. This is likely a pun on Ramen soup (RAM-in-soup).
There is a Persona 5 reference where you enter Midtown, you can find a robot named 'Sojiro' and he would state that he "used to own a bar." Sojiro in Persona 5 did own a bar, technically a café, called Leblanc. Sojiro also says he "took a screwdriver to the knee", a reference to a line often said by guards in The Elder Scrolls V: Skyrim (2011).
The protagonist in Stray had its design based on a real cat named Murtaugh. He is the cat of BlueTwelve Studio's producer, Viv and Koola. Originally he was a stray himself, found by Producer Martin-Raget under a car near Montpellier, France
Stray features a companion drone named B-12 that helps the cat interact with the environment and translate robot languages.