Given how many Taiwanese are probably already on the Chinese payroll, I'm guessing they would go with a Little Green Men type hybrid attack prior to the real invasion. Take control of a couple of ports, and cripple command and control of the military, and just roll in with their enormous commercial fleet just after the first amphibious assault. They are producing a lot of amphibs, but still not enough to go it alone with them for an invasion. Get even two of the smaller ports and an airfield or three taken by commercial flights carrying troops, and it would game over very quickly. I've only been to Taiwan once, but it was eye opening to see how tied they are economically to China at every level, given that they are still "at war".