Finally got this coloured.  
Wanted to get this done before trying out the DB collab thingy.
 
You might notice that I tried to stay close to the respective originals, such as…  
…the conformation of the pony  
…black vs dark coloured outlines  
…solid vs gradient irides
 
I also fiddled around with different techniques.  
Most parts of Twilight Sparkle have multiple layers of colour, up to seven that is.  
While Twilight often has a single colour only, where lighter parts got filled by applying estompes (paper rolls).
 
I wonder if I should have drawn a background.  
It would need to be subtle that doesn’t take the focus.  
Maybe some faint blue and green colours hinting sky and land?  
Or should I just leave it as is?  
Do you have any suggestion?
 
Uncoloured version:  

 
References: