Looks okay in general Muse, and my niggles with it are fairly minor.  I'd say that if Riana was the product of a human/twi'lek pairing, she would end up a a half-breed (aka Near-human in terms of race); however, I figure a fairly good, and minor, fix would be that if her father was a half-human/half-twi'lek near-human, it would be reasonable to assume his children with his twi'lek concubine would be full twi-leks with maybe minor cosmetic alterations (yeah, yeah, I know; genetics doesn't work like that but hey... fiction!)