She calls every girl in her clique by their first name. And sometimes sarcastically teases them without the individual's knowledge. She genuinely cares for her friends which is shown by her actions in the light novel and anime series.
She also wished for an unchanging environment in her clique like Hayato and Yumiko.
Yui and Hina are shown to be good terms. Yui is able to get Hina to assist the Service Club whenever she calls for help. Usually at the request of Hachiman. In the anime they are seen together occasionally.
Yumiko and Hina are close friends, they often spend time together. Yumiko is able to tolerate Hina's Yaoi fantasies to a certain extent. Yumiko is the one who always stops her from getting overexcited. Yumiko is also one of the few to know the crafty, sly side of Hina.
Yumiko and Hina are shown to be shopping in Episode 4 of season 2. Yumiko also tried to setup Hina with boys that were interested in her, but soon learned that it will deteriorate their friendship and discourages Hina. Both of them genuinely care for each other. Hina also encouraged and escorted Yumiko to the service club to help her make valentines chocolate for Hayato. Hina consoled Yumiko during the rumours of Hayato and Yukino which greatly disturbed her.
Tobe seems to be interested in Hina. In Volume 6 and the first arc of season 2, there are hints of Tobe trying to get close to her. Tobe later planned to confess to her during their school trip and requested the Service Club's assistance. It was later revealed that Hina knows of Tobe's feelings towards her, but does not want to engage in a relationship at the current time due to her lack of confidence in herself, and thus requested help from Hachiman to help her maintain the status quo. Hachiman succeeds. But even so, Tobe isn't ready to give up on her. Tobe still tries to make passes at Hina. Hina also tried making valentine chocolate in the pre-valentines day event and offered it to Tobe, since Tobe hinted for some Valentines Day chocolate from girls. Hina calls Tobe by the nickname Tobecchi.
Hayato and Hina are shown to be on good terms. They call each other on first name basis. Once Hayato tried to escape a lead role in Hina's play during their class' cultural play without success. There are hints throughout the anime and light novel that Hina requested help from Hayato to stop Tobe from confessing to her. For which he tried to a certain extent before requesting Hachiman's help.
Hina seems to be fond of Saki. Saki is the first girl Hina befriended outside her clique. After the cultural festival she acknowledged Saki's talent in making costumes and her attention to detail. Ebina fondly calls saki "Sakisaki" to the latter's annoyance. She relies on her for costumes and wardrobe during school events. She dragged Saki to her group during the field trip. Hina also has some knowledge of Saki's family, though Saki is a private person.
He is the co-worker with whom Ebina worked with on the athletic festival committee. They were in synchronous in finding new events for the festival. Their relationship is like office co-workers and nothing more. They were able to get along well till the end without any conflicts in the athletic festival committee. Even their actions were synchronous sometimes. They are not shown or mentioned to meet or talk after the athletic festival.
Ebina - just like Hayama - calls Hachiman "Hikitani". She also wrote Hachiman's first name correctly in the Service Club's survey for the Love and Marriage column of a magazine. She seems to like the idea of Hayama and Hachiman being a couple due to her love for Yaoi and she always makes strange giggles whenever they are seen together. This infatuation about them started only after the cultural festival and not before.
When she learns that Tobe is about to confess to her, she indirectly requested Hachiman to stop Tobe from confessing to her in-order to maintain her clique's status quo. She thanked Hachiman personally when it was done. It must be noted that she is the second person to thank Hachiman next to Hayama (chain message incident). Ebina eventually told him that she hates herself for always being selfish with her desires and that she is rotten. It's also suggested in the anime that Ebina has romantic feelings toward Hachiman and is somewhat surprised when he interprets her affectionate comments (sweet nothings) as "sarcastic".
Hina and Hachiman again have a private talk in Destinyland, where Hina tries her humor of Tobe x Hachiman then apologizes for the awkward situation of the Service Club, which she believes to be her doing. Hachiman tells her that it didn't matter and asks about her, to which she thanks him again as her clique is doing well after his involvement (with Tobe's confession). Despite the fake confession incident, both have more or less formal greetings and which Hachiman refers to her as being a somewhat nice girl.
She sometimes shows her true nature to Hachiman, when they are alone which is more serious than her usual happy behaviour with Yui and Yumiko.