I think Spike as Simba is cool and all, but I prefer Twilight (Unicorn and Alicorn alike) as Simba (because Twilight is Best Pony [and my - read, MY - Waifu).
 
My MLP/Lion King Cast;
 
Simba - Twilight Sparkle (Unicorn Twi as Young Simba, Alicorn Twi as Older Simba)
 
Nala - Applejack (‘cause TwiJack needs more love!)
 
Scar - Princess Luna/Nightmare Moon (Luna is Best Princess, after Twilight and Clestia, of course)
 
Mufasa - Princess Celestia (like another Background Pony said, Momlestia is best Celestia)
 
Sarabi - Twilight Velvet
 
Timon - Rainbow Dash
 
Pumbaa - Pinkie Pie
 
Zazu - Rarity
 
Shenzi - Nightshade, leader of the Shadowbolts
 
Banzai - Stratus, second-in-command of the Shadowbolts
 
Ed - Bluball Blitz, the (presumably) fastest of the Shadowbolts
 
Rafiki - Zecora (Obviously. I mean, who else is the ‘wise shaman’ [shazebra?] type of character?)
 
Sarafina - Dusk Shield (OC)
 
Lionesses - Derpy Hooves/Ditzy Doo, Lyra Heartstrings, Bon-Bon, Vinyl Scratch, Octavia, Colgate, Roseluck, Aloe, Lotus, Sunset Shimmer, Sapphire Shores, Fleur de Lis, Cloud Kicker, and Spitfire
 
Hyenas - All other Shadowbolts
 
The Loyal Subjects of the Pony Lands (yes, that’s what I call the MLP version of the Pride Lands. Please don’t steal any of my casting choices or ideas.) - All other Background Ponies, Side Characters, and Popular Bronies/Pegasisters’ OCs.
 
(If you wish to write a story based on my casting and ideas, you can, but you MUST give me full credit for the cast and all inspiration for the story [besides the obvious copyrighted material that obviously belongs to Hasbro and Disney], okay?)

Spike, Dragon Princess of Equestria.

Neck is kind of weird, but nice image.

the lion king! pony style!

And then Spike was the new ruler of Equestria.

momlestia is best lestia :3

Lol cute!