Weather - Hurricanes suck up water from the ocean. When they cause rain over land, is the rainwater

You need to review your science studies and learn to use the words correctly. Hurricanes do "suck up" water, but it has nothing to do with rain. It is called "storm surge" and it is a totally separate subject. Water evaporates from oceans but salt does not. Evaporation increases when temperature rises, not directly associated with a hurricane. Salt does not evaporate, so rain water is pure except for dust that happens to be drifting in the air. So you just need to learn what the words mean.