iirc Game Maker 2 does a good job of scaling art down, but it is good practice to draw at the size you want your sprite to eventually end up being, that way you can control which details "get lost," instead of drawing big, scaling down, and then having to make adjustments. Ends up just being more work.
What is the ideal size of the player? You don't want him too big because it limits the level design of your platform segments. Perhaps you could make two versions of him? A smaller chibi version for the platforming segments and then the size of sprite7 for the fighting segment?