Honestly, the "there's not much you can do with 16x16" in this case sounds more like an excuse than anything else. Yes, the drawing area is extremely limited, and there's not many different ways to do create single unique character. But there's not even remotely close to
one right way to do it. Your character has the exact same dimensions, proportions, and pose as Link, even when comparing them pixel by pixel, to the point it's basically instantly recognizable as being just a modification.
Try learning from the sprite instead of just copying it. Use it as inspiration, but don't let it dictate exactly what you should do. There's a ton of different ways to give a character personality and making it unique. Imitation is actually pretty good for practice, but you should definitely go for something original once you manage to understand how it's done. Just
try to do something different from scratch instead of modifying what you already have. You might even surprise yourself at the results!