I saw this initially, but didn't post until now. Lots of emotions in your post. Not much that I can say that hasn't been eloquently stated already. I am so sorry.
I feel that I can share now. My father passed from cancer when I was 16 (he was 42). They let us, the family, take one last look before closing the casket. I still regret not loosening his tie. It was always the first thing he did when he got home after wearing a suit, which was rare. It is still surreal that I am older than him now.
Please be kind to yourself, and help each other. Grieving is different for every person. You absolutely did the right thing with the button.
Take all the time you need, and don't let anyone tell you differently.
TAG