I would also regret seeing those cute buttons and not buying them. I used to craft stuff and I found that glue doesn't hold hard items to fabric items long term. Even hot glue gave way after a while, especially on Christmas decorations. Possibly the handling of unwrapping them and rewrapping them in tissue when I stored them away until next Christmas? Anyway, I say that because maybe when you are back in the mood for a little hand sewing you may want to sew those buttons on so if the glue does let go over the years you won't lose any of those cute buttons (which I bet you would have a hard time replacing!).
Edited to add, I love how you fussy cut the star fabric to put a star in the middle of each cornerstone. Those little touches made a big difference.