I am not a teacher but I think that you are right. Sentences from 2 to 4 are correct (at least for me), but like you said there might not be such collocation as 'get rid of heat'. I suppose that 'get rid of' refers to the situation when you make something disappear, and not bother you any longer. So, by implication, you cannot make heat disappear.
Concerning the second question, I would stay with the phrase "the Taiwanese" because it looks more formal, and generally means the same when you would say "Taiwanese people".
Probably, you have to make sure about this 'get rid of' collocation, because as I said, I am not a teacher and I could make a mistake.
I hope I was helpful.
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