I've decided to make Sarafina and yet-unnamed-TLG-cub be mates, and Nala's parents. I've combined the fanon/my's love of Sarafina/Scar, the fact that Scar's Guard died, the non-evil-Scar theory, Zira's personality, and a few other things for my theory. Scar liked Sarafina, but was betrothed to Naanda. Sarafina was friends with Scar, but took Nala's father for a mate. Scar killed the Guard, including Nala's father, and when he took the throne he declared not Naanda, but Sarafina his queen.
Naanda was understandably pissed (Zira was to be heir, she was pregnant) and so was Zira (who was a teen at the time). Sarafina was embarrassed, but she and Naanda had never been great friends (Naanda had a jealous streak and Sarafina a dislike of outsiders) and she knew it would be a great opportunity for Nala (who was named heir).
Scar and Sarafina have Mheetu, who is now the official heir. Nala, as a Princess, is eligible to be betrothed to a nearby pride's heir. After Sarafina's death, Mheet