Note that there are three National Parks where a most prominent peak is impossible to determine:
The extent to which there are local maxima on the ground surface of these areas is very low, and in the swampy areas there may be quite a bit of change. So it seems best to leave there three parks off the list.
The low and swampy Key Biscayne and Dry Tortutagas National Parks are on islands, so the island high point is also the prominence point.