Hi EER,
So I got a chance to try out what you recommended. It almost worked 100%. It did not change the gradients as you anticipated it might not.
I messed with the tolerance but anything above 21% and it would change the green to another shade. Anything lower than 20% (19% and lower) and it would convert less of the yellow.
The HEX color I am trying to convert to is 98C224 (RGB: 152, 194, 42 or HSV: 76, 78, 76). The yellow in the image is F6D40E (RGB: 246, 212, 14 or HSV: 51, 94, 96).
Below is a zoomed in image (1200%) comparing the original with the result after using the recolor tool at 21% tolerance. You can see that there are still some yellow pixels floating around. And I just noticed that in this image, the yellow fades to white, not to transparent. I got confused with another button. sorry about that.