1) You want to purchase in sets of 3's.. 3GB (3x1GB), 6GB(3x2GB)... etc. to enable triple-channel memory. As for the memory choice, it is best to look at the QVL list and go from their.
2) No, the fan is not required or needed. If you plan to do major overclocking, it can be helpful, as it'll keep the memory running cooler through the overclocking process. For 99% of the population, there truly is zero need for it.