1C2S was Deng Xiaoping's (and Jiang Zeming's) biggest mistake in regards to Hong Kong. Look where that autonomy got them: courts where judges are foreigners, an education system that shits on the mainland, foreign "NGO" presence out the ass.One country, two systems is the offer if there's peaceful reunification. The deal would probably be significantly sweeter than what Hong Kong got since Taiwan has much more leverage. Of course, with every passing year they lose a little bit of leverage. I don't think the CPC even needs to impose any laws on Taiwan, they can continue with their current mockery of democracy as long as there are some PLA bases on the island and they give up the idea of independence.
If there's a war, it depends on how radicalised Taiwanese youth become. There's probably a significant minority of them who are a lost cause. They should be encouraged to emigrate so they don't cause trouble and everyone who does want to fight should be reeducated. However, I wouldn't reeducate people on Taiwan, send them somewhere to rural China so they can mingle with their compatriots and are less likely to rebel on the island.
Even if a war is required for liberation of Taiwan, Hong Kong style 1C2S with NSL is probably still best. You'd want to minimise the shock for civilians. If they feel that nothing much has changed and they can live their lives as before, people will accept it and not rebel
No, 1C2S was basically an acceptance of the UK taking HK by right of conquest. Why should a thief ever get a vote? Likewise as the losers of the civil war, the Taiwanese would be in no position to demand concessions from the victors.
How you really pacify a population is by improving their quality of life so that they risk destroying their gains if they rebel.