Given what Li Ao did after Taiwan democration, he became ATL Chinese head of state gave chill down my spine. Being Fortunate Son of Imperial Japan cozy Formosa Family, Lien Chen won KMT presidential nomination and won the election as well also felt ASB.
Li Ao is certainly an interesting character, and I'm sure that readers who look him up will be surprised at some of what they learn about his later life. Basically everything went right for Li Ao in order for him to win in 1990, and in normal circumstances he wouldn't have gotten anywhere near power.
As for Lien Chan, his father was an important figure in the government OTL and TTL. This gives Lien a lot of connections, and he also serves within the Chiang Ching-kuo and Wang Sheng administrations. He avoids doing anything controversial in the Summer of 1989 and becomes a unifying figure unlike Wang Sheng, Hau Pei-tsun, or Liang Surong. He gets the support of those who want to keep the KMT from being a Chiang Dynasty as well. That was my reasoning for Lien Chan winning the nomination. And then he wins the election due to Li's unpopularity (but only barely because the KMT is also unpopular in 1996).