Got inspired by Helm's cluster study process video and decided to try it myself 

I kept original resolution restrictions and colorcount, though I changed the colors and dropped one green shade for Olaf and Baleog. Also I tried to make their poses a bit more dynamic, and changed the vikings' appeareances a bit to my personal taste, I always prefered Baleog's face on the cover art rather than in the in-game sprite with his huge lip and kinda Genghis Khan's moustache 

Probably could've worked more on the selective outline, because despite looking fine against pure black or white backbgrounds, it still could blend in with some colors in a couple of places 

Here's the version with the original SNES color palette: