Actor Sebastian Stan and Actress Jennifer Lawrence canonically exist in the universe of the show. Yuji mentioning his taste in women to be similar to Jennifer Lawrence and Momo having an infatuation with Sebastian Stan.
Yuta has been mentioned to have been training somewhere in Africa with Miguel but not exactly where, well the second opening of season 1 shows Yuta and Miguel in Chefachaouen which is a Moroccan city.
Aya Endo, the voice actress for Shoko, on her significance to Satoru and Suguru: "For Gojo and Geto, having someone who would stand by their side no matter what happened was a source of certainty."
The creator Gege Akutami can't picture the character of Gojo being faithful to a certain women, implying he might never get a girlfriend.
Although the movie prequel "Jujutsu Kaisen 0" was released after season 1, the pilot comic which it is based on was released before the main Jujutsu Kaisen comic began (which the TV series is the adaptation of).