While the two didn't have the best relationship, the two did seem to get along. He learned to steal for and from his dad and Jafar didn't seem to treat him too bad, though it was shown he never gave Jay a bed and he had to sleep under a shelf of tvs which could've easily dropped and killed Jay.
Carlos is Jay's best friends. The two are usually seen hanging around each other and interacting positively though they tend to get into fights throughout the film due to Jay's aggressive dominating thieving personality. The two fought with each other over eating candy in the limo and then Jay tried stealing a jacket Carlos wanted. The two both enjoyed playing video games. The two also joined the Tourney team though Jay was far more successful due to the skills he acquired from thieving. However, after being taught by the coach that being a team meant working with each other, Jay insisted Carlos be included in the game and the two won.
Mal is the leader of the reformed VKs so he often followed her lead. She often had to remind him to focus like when he was playing video games. She was also annoyed when he tripped the alarm trying to impulsively steal the wand. She got annoyed with his stealing and simple mind, telling him he didn't need to because they would rule and he could get them later. She also had to remind him to stay focused when he considered staying at Auradon Prep. Despite this the two are shown to be close friends as she cheered for him when he won the Tourney tournament with Carlos. She also managed to convince Jay to join the good side as she understood him well enough to know he enjoyed being on the Tourney team and being at Auradon.
In Wicked World, she was shown to get along with him still and was concerned when he and Jay didn't come to pick her and the others up to the Neon Lights Ball and glad to know he was alright. Overall, she seems to act like a sister to him. He also helped her break away from her mother's curse.
While the two did not have much interaction during the show or the movie, the two were shown to get along. She cheered for him during the Tourney tournament and when Chad was bullying Evie, Jay came to her defense, showing he cares for her as a friend. In the book series, Jay, Evie, along with Mal and Carlos go back to the Isle together after a while in Auradon.
In the first movie, Lonnie and Jay don't interact much at all except for the scene where the VKs are making the love potion cookies and Lonnie comes in and taste tests it. Jay tests the potion and tries to flirt with her but she dismisses the action.
In Descendants 2, Lonnie (due to her love of fencing) begs Jay to be part of the Swords and Shields team after defeating him during practice, but because of Chad Charming and his rule book, Jay disagrees. Lonnie also convinces Jay to take her with him to the Isle and help fight Uma to save Ben. After Jay saw her fencing skills, he stepped down as captain of Swords and Shields and rewarded her with the title of captain of the team. Jay supposedly had no date to the Cotillion, but he is seen with Lonnie meaning that he probably asked her to be his date. At the end, they are seen sharing looks, dancing with one another, and hugging at the really end of the scene.
While the two didn't interact much, she held a low opinion of the VKs. Despite this, he flirted with her in the beginning of the film and she cheered for him during film when he scores victory for the team and and at the end of the film, Audrey shows her acceptation of Jay by flirtatiously dragging him on the dance stage. He also tried complimenting her hair in Episode 4 when it looked terrible though admitted it didn't look good, saying he was just trying to be nice. In Episode 15, Jay along with Carlos were supposed to pick Audrey along with Jane, Mal, Evie, Ally, Freddie and Jordan up to take them to the Neon Lights Party, but failed. In Episode 17, Audrey, along with the other girls, asked Jay and Carlos what happened to them and when the boys explain, Jay agrees with Audrey's comment about Carlos' Dalmatian Tucks.In episode after CJ escaped they stood next to each other in the group-selfie. In episode 24 when accused Mal turning Evil Again he told Audrey she didn't want throwing to ruin her beautiful face, hinting he may have feelings for her.
While the two don't interact much, the two were shown to get along well in the film. Ben tried to socialize and be friends with all the VKs and he helped Jay get ready for the Tourney tournament . The two are shown to interact positively and in Wicked world episode 10 he let Jay hit Carlos for not helping them when they were turned into dogs until Mal pressured him to help. He was also worried for Carlos and Jay when the showed up late to the Neon Lights Ball, saying he was really worried about him. Strangely though, he keeps calling him Jordan as shown in episode 17.
She held an initial fear of VKs, and y extension Carlos. After the Family Day incident she wasn't above ridiculing the VKs out loud but mostly Mal. During the end of the film, she accepts the VKs and Jay and Carlos even invites her to dance with them though she is later seen dancing solo with Carlos. She was worried though in Wicked World that the carpet he was supposed to take the others in to the Neon Lights Ball might be stolen.
He had no interaction with him but it can be implied they got along due to their association with Evie.
He doesn't have a high opinion of Jay, as he was a VK and Jay in turn didn't like Chad though they were able to get along during the Tourney tournament. When Chad harassed Evie and Mal, he jumped to their defense.
They have had little interaction though she didn't hold the highest opinion of him as he stole her lamp and assumed the carpet he was supposed to pick her and the others up in was stolen. Despite this, in Return to the Isle of the Lost, there are hints he has feelings for Jordan.
The two didn't interact much but it is presumed they are friends especially since the two are VKs. She also seemed amused at the aspect the carpet he was picking her and the others up in was stolen.
The two had little interaction, but she was shown to be distrusting of VKs and annoyed when he and Jay didn't come to pick her and the others up (not knowing he was carpet jacked). She also admitted to not worrying about him when he didn't show up showing how rude she is.
He was impressed to find out she carpet jacked him and Carlos and tried flirting with her, though she wasn't amused since he was interrupting her soliloquy. He was upset upon learning she framed Mal for all the bad stuff she did.