The hat looks cool. In the original, it is ambiguous where the tail is given the limited colors. The tail might therefore be at the back, which is slightly more ghostlike, and slightly less speech-bubble like. In the blown up version the tail could be at the back, then. In the originals, the squareness is less, and the tails are thicker, so there's some leeway to experiment with these to make it more ghostlike. The tiny versions are presumably more abstract than the cutscene versions, so there are probably a few more little details you could add to hint at ghost.
One other thing I notice is that the cutscene version is way higher contrast and way higher resolution. I'm not sure it would feel in place in a game with the smaller sprites. Difficult to see without seeing the original game, but maybe these are things worth considering.