The question is really not that clear.
All I can do is shoot and hope to hit something, for I don't know what you are reaaly asking.
Would pinning the buttons to the sprite work?
If you'd like to resize the buttons the same way as the sprite it would mean calculating the size of the sprite compared to it's original and multiplying your button with that amount.
so first you would need the sprite's original size.
setting instance variables for originalwidth and origanalheight before changing it's size would do that.
to change the button it would look something like this
button set width - width= (sprite.width/sprite.originalwidth)*button.width