The holes in the buttons give loads of opportunities. You can insert small pen shaped turnings into the holes to add contrast and texture. You could wrap thread through the holes as though the button were sewed onto the wood. You could use alternate materials like copper wire for the threading. Consider what impact buttons have had in your life, holding up your pants, closing up a collar to protect you from the cold, polishing brass buttons on a uniform... Figure what the impact is and then figure how that impact can be depicted. For example a black button on a white wood like holly with the holes filled with the color of your wedding. When you think in these terms the shape of the bottle stopper becomes more meaningful as well.
This sounds like a lot of effort for a bottle stopper but when you put a piece of you into something as simple as a bottle stopper you will be making "stuff" at a whole new level.