I'm thinking that if a European power held onto Taiwan for any period of time, it would alter the racial dynamics considerably, but not in the way people think.
Basically, I think the Dutch (and later, perhaps the British, or someone else) would want to do everything they could to keep Taiwan out of the Chinese sphere. This would probably entail some level of white settlement, but quite likely a lot movement of laborers from elsewhere in Asia. Establishing plantations which drew on a mixture of Indians, Malays, Javanese, and a smattering of African slaves, perhaps, would make for a highly diverse populace which wouldn't want to be part of China, but also wouldn't be a good fit anywhere else.
The end result would essentially be a giant Trinidad, Suriname, or Mauritius - a veritable constellation of races, with numerous examples of admixture. Europeans might leave at de-colonization, but could also stick around and remain the economic elite. The lingua franca would probably be a European tongue or some creole derivative, although it's unlikely Christianity would develop into the overwhelmingly dominant religion, given such a heavy leavening of Muslims and Hindus.