I barely played the game but here goes. The main protagonist, Oliver, is trying to save his mother and learn how to be a wizard (Twilight fits his role, perfectly). His companion is Drippy, a creature that was cursed to be a doll. Oliver’s mother gave Drippy to him when he was very young and after his mother passed away, Oliver broke Drippy’s doll curse (Ms. Smartypants could be him). Next, Oliver gets his own little monster ally called a “familiar” to fight for him (Spike fits this role). Lastly, the main villain (at least I think she is) is an evil looking queen with a robe that has a galaxy/night sky appearance (Nightmare moon could be her).
 
I don’t know about Oliver’s other friends later in the game, though.

The aforementioned ‘White Mare’ is obviously Celestia (due to the artwork), but it could be implying Rarity or Vinyl. Though, wrath of an alicorn would be worse than that of a unicorn.

@Background Pony
 
Why? I haven’t played the game (yet),but I’m curious.

@Background Pony  
I want to play it but I no has last gen consoles ):

Saw this coming ever since I first played this.