Ashura's gender is sometimes debated by fans, especially after Tsubasa Reservoir Chronicles where he stands as the guardian of a female tribe. In RG Veda Tokyopop opted to define Ashura as male, but CLAMP's original intention in both versions was for Ashura to be genderless and ambiguous. So technically you can see him/her however you wish. The grand majority of CLAMP fans view Ashura as male, myself included.
Yasha's wounded right eye appears in both RG Veda and TRC. In RG Veda is a wound that he gains after Ashura sacrifices himself to save him and is never fully explained how he gets it. In TRC Ashura gives him the wound in a fight after Yasha is weakened by a disease.