Lion King prequel

The Lion King prequel is a so far unnamed movie idea by Boofersonj.

Introduction
So my kids love the new Lion Guard show on Disney Channel that is about Simba's kids. And while they added some backstory to Scar, and why he was so power hungry for the throne, they never attempted to say how or why he became aligned with the hyenas. I started developing a backstory in my mind well before this Lion Guard came out, and while it still mostly fits my vision, I think it can still be done with minimal changes to fit the new continuity. Thus I present to you, copied from my blog, my vision for The Lion King, a prequel:

Plot
Scene opens to the sun rising over pride rock. The king is already looking out over his kingdom, and is soon joined by his queen. They look back to their two sons, still sleeping, and discuss how today is the day that they begin grooming their eldest for his ascension to the throne by teaching him the circle of life. The king tells his kids to follow him, but the younger cub runs off to the watering hole overly excited. His brother tries to catch up, but by the time he gets there a crocodile is already stalking the youngest lion. Big brother tries to save him, but his throw clear and knocked out while little brother runs home scared. A vulture, thinking the cub dead, carries him off. The king sees this and thinks the worse. He returns to pride rock and shares the bad news with his wife. Then he tells his youngest son, Mufasa, that he will be the next king.

Meanwhile, the older cub wakes up and shakes himself free of the vultures grasp... only to land in the hyena den. The hyenas lock him in captivity while they fight amongst themselves. Who gets to eat the lion, or should they hold him for ransom, or use him as bait to set a trap for the king. There is no leader, so they continue to bicker without coming to a decision. They eventually grow too hungry to debate, and bring in a zebra for dinner. During the frenzy some scraps are accidentally thrown towards the lion. A hyena swipes at the Cub to steal them back, cutting the cub over his left eye. The hyenas laugh and tease the lion, calling him Scar. The cub stands up, roars, and knocks down the hyena holding his claws to the animal's throat. He orders the others back, and to his astonishment they obey!

The next part of the film shows Scar growing up to lead the hyenas, learning to savage, hunt, and eat whenever possible; while Mufasa learns to protect the circle of life and becomes a powerful king, though filled with regret. Eventually the brothers are reunited, and while Mufasa is elated to find his brother alive and thus relieving the guilt that has plagued him for years, Scar is jealous that his throne has been stolen and thinks Mufasa planned this all along. He plans to take back what is rightfully his when Mufasa is dead and forms the Lion Guard to help him, until he learns a prince has been born...