Hadad: This variation is occasioned simply by the mutation of ר, raish, and ד, daleth; being in Genesis, הדר [Strong's H1924], Hadar, and here, הדד [Strong's H1908], Hadad. Gen 36:39, Hadar Pai: i.e. sighing, [Strong's H6464], This simply depends on the interchange of י yood and ו wav; being written in Genesis פעו [Strong's H6464], Pau, and here, פעי [Strong's H6464], Pai. Gen 36:39, Pau