Short answers, pulled from the story.
Confucianism is a system of thought and behavior originating in ancient China, variously described as a tradition, philosophy, religion, theory of government, or way of life. It was founded by Confucius during the Hundred Schools of Thought era, around 500 BCE, with a core focus on virtue, social harmony, and familial responsibility.
The Five Constants are the core Confucian virtues elaborated by Confucian scholars during the Han dynasty. They are ren (benevolence), yi (righteousness), li (propriety), zhi (wisdom), and xin (sincerity).
Tian, translated as Heaven, is a transcendent moral order rather than an omnipotent personal deity. Confucius used the term in a mystical way, writing in the Analects that tian gave him life and watched and judged him, and the scholar Ronnie Littlejohn warns it should not be read as a personal god like that of the Abrahamic faiths.
The Confucian examination system was abolished in Korea in 1894, in China in 1905, and in Vietnam in 1919, which meant Confucian ideology was no longer required for a government career. Chinese reformers came to associate Confucianism with China's Century of Humiliation and embraced alternative ideologies such as Sun Yat-sen's Three Principles of the People and later Maoism.
The junzi is a Chinese term literally meaning son of a lord, redefined by Confucius in the Analects to describe a person of noble character and ethical virtue rather than noble blood. The Song dynasty philosopher Zhu Xi defined the junzi as second only to the sage, and it stands in contrast to the xiaoren, the small-minded person who seeks only immediate gains.
Confucianism largely defined the mainstream discourse on gender in China from the Han dynasty onward, prescribing the Three Obediences and Four Virtues, by which a woman was to follow her father, then her husband, then her sons. The Song dynasty intensified the value of chastity, with the Confucian Cheng Yi writing that to lose one's chastity is a great matter, though figures like Ban Zhao, who lived from 45 to 114 CE, also presented education as important for women.