From MangaHelpers

Kazura has her first high school boyfriend, a cute guy named Iwasaki who likes her very much. When he takes her to see her favorite band perform live, she meets the band's cool, attractive vocalist. The next day at school, she discovers a secret: the sexy vocalist is none other than her teacher, who seems totally uncool in his daytime appearance! What will she do about her boyfriend, her teacher's secret, and her growing attraction to him? [tethysdust]

From MangaHelpers:

Takahashi Kiji is an attractive, popular, student council president, but he and his two closest friends are bored. Kiji comes up with a game, "The Prince Game." The goal is to bring the worst girl ever to his birthday party in a month. Kiji begins trying to romance the friendless, round-shouldered, weepy Asahi Mabi, who has just been through a harsh breakup. To his surprise, Mabi does not immediately swoon into his arms. Instead, she seems to be a human being, with her own thoughts and goals. She is uncomfortably good at seeing through some of his act. Seducing Mabi requires getting to know her, which is dangerous when his intention is for her to end up in tears...

Instead of her father, Hina is the one running the duties of the Building Manager in "Apricot House". One day, Hina accidentally destroys the keyboard of room 304's strange resident. Hina is then asked by this strange guy to run errands for him as reimbursement. In truth, the resident of 304 is the charismatic vocalist of a popular band... What will be his true face!? What will Hina think once she sees him sing on stage?

(Source: The Paper Dolls Project)