TAIWAN'S President and Kuomintang chairman Lee Teng-hui has appointed four senior - and often controversial - politicians to be vice-chairmen of the ruling party. While none is a surprise choice, their appointments will have a profound impact on the development of the island's politics, including the campaign for the next president. Here are brief biographies of the four: Vice-President Li Yuan-zu: A trusted aide of the president, Mr Li's elevation to the first vice-chairmanship will help the party chairman in consolidating the hold of the so-called Mainstream Faction. A former law professor with a doctorate from Bonn University in Germany, Mr Li, 70, will be acting party chairman if his mentor is away from Taiwan or is incapacitated. Mr Li's extremely low profile has prompted a local manufacturer of air-conditioners to advertise its products as being ''as silent as the vice-president''. However, the powers of the former justice minister has grown steadily. Mr Li has given President Lee decisive advice in vetting candidates for promotions, and in official endorsement for the running of legislative and other positions. Mr Li, because of his age and his lack of a power base, is not expected to rise further. Former premier Hau Pei-tsun: The vice-chairmanship was the ''consolation price'' President Lee reportedly offered Mr Hau in return for the latter's agreement to stepdown from his government post last March. A head of the so-called Non-Mainstream Faction of the party, Mr Hau's efforts to boost the powers of his clique has been rendered difficult by the decision earlier this month by several Non-Mainstream politicians to break away from the KMT to form the New Party. Since his retirement from the position of head of government, Mr Hau, an ardent opponent to Taiwanese independence, has retreated from the media limelight. However, Taiwan analysts said it would be a mistake to underestimate the one-time chief bodyguard to Chiang Kai-shek. During his tenure as premier, he earned the respect of businessmen and ordinary citizens for dramatically bringing down the crime rate. The former general, the father of Taiwan's weapons modernisation, still commands the loyalty of a large number of senior army officers. Judicial Yuan President Lin Yang-kang: The vice-chairmanship of the party is the price loyalists of President Lee is most reluctant to give Mr Lin, an ambitious and popular native-Taiwanese politician. A former governor of Taiwan, Mr Lin, 66, is one of few senior KMT politician who can mediate between the various factions of the party. He is also popular with local ''warlords'' in central and southern Taiwan. Should President Lee not run for a second term in 1996, Mr Lin may receive the blessings of powerful Non-Mainstream politicians, including Mr Hau. In spite of his relatively young age, Mr Lin had seniority over Mr Lee in both party and government positions before the late president Chiang Ching-kuo appointed Mr Lee vice-president in 1984. Premier Lien Chan: Mr Lien's elevation to vice-chairman should consolidate his standing as the leader who has a good chance of leading Taiwanese politics into the next century. A protege of President Lee and scion of one of the most powerful clans in Taiwan, Mr Lien, 57, may also receive the former's blessings to run for president in 1996. While critics say Mr Lien has not distinguished himself in his previous positions as foreign minister or minister of communications, the premier has been dubbed ''Mr Lucky'' for his extremely smooth ride to the top. Mr Lien, however, is not a charismatic leader, and his political chances may be hurt by the fact he is one of the richest men on the island. Mr Lien has a doctorate in political science from the University of Chicago.