Since no one seems to bat an eye or mention Fatima's pointed ears, perhaps they aren't as uncommon as one may think. While no one else has such ears, it seems that people with Shadow Frost magic are also uncommon. Witches and Wizards are apparently just humans with high aptitudes for magic, but it also seems that this ability to use magic somewhat changes a person's physiology. It has been stated in the game that magic aptitude is genetic. This is stretching it, but since the ability to use magic is genetic and thus a mage's body chemistry is different from that of normal people, then perhaps the powers of Shadow Frost outwardly changes its users a little, such as making their ears pointed. Or the genes for Shadow Frost magic are linked to the genes for pointy ears. It also fits with users of Shadow Frost being somewhat ostracized by people. It would be easier to tell and avoid a Shadow Frost user if they had an obvious physical trait, like pointed ears.
Although Bharva is the King of Beast Fiends, Althea is considered the perfect Fiend, yet she is apparently very similar to the King in beast form. Perhaps Bharva was Elicia's then-attempt at a perfect living being. Perhaps she used too much magic to create this not-quite perfect Beast Fiend and that caused a wave of magic to mutate all living beings in its range. Bharva did say that he is the "embodiment of Ahrtania." Perhaps, among other things, he meant that to mean that Ahrtania was created along with him, or because of him.