Would Confucius have agreed with the ideas of the Sunni Muslims or Shiite Muslims?

Answer 1

It is worth noting that any answer here is pure conjecture. Confucius had nothing to do with Islam or the split between Sunnis and Shiites. The split between the Sunnis and Shiites was due to political disagreements over who should rule. Confucius' words and concepts can be molded to support either side, see below.

Pro-Sunni View:

According to Confucius, a pious man is internally governed by the Te and a use of this Te leads to the perfect organization of government structure. A person who can maintain and govern his body and self loyally can expand these virtues to the governance of the state. This comes through three general requirements for a government: maintenance of economic self-sufficiency, military strength, and gaining the confidence of the people. In these three aspects, the Umayyads excelled. The economy grew substantially with the integration of former Byzantine and Sassanian bureaucrats. The Umayyad military successfully vanquished its adversaries in the Islamic Civil War, in Anatolia, Central Asia, and Iberia. The Umayyads also helped to establish the system of Qadis and Faqihs that created loyalty and confidence in the Islamic States.

Pro-Shiite View:

According to Confucius, there are five relationships that need certain behavior. One of these relationships is the one between rulers and subjects. The ruler is to be benevolent to the people. While the Umayyads were certainly good societal engineers, they were horrible to their citizens, especially when they massacred Hussein and his family. They were authoritarians who were violent and uncompromising. 'Ali, by contrast, was very well-received among the people and favorable towards them. He tried as best as possible to respond to requests to look into 'Othman's assassination, he came to negotiate with the Umayyads during the Islamic Civil War even when he had superior military strength, and he tried to pacify militant factions throughout the empire.

Additionally, the Confucian Concept of Chun-Tzu or the Ideal Man closely mirrors the Islamic concept of piety in which 'Ali excelled. There are five virtues that come with the sublimation of ego such as kindness, rectitude, decorum, wisdom, and sincerity. These attributes map better onto 'Ali than any of the other Rightly Guided Caliphs and certainly better than the Umayyads.