Well, I couldn't move on. There's nothing more aggravating than working on a project that doesn't turn out the way you want it to.
So I redid it again. I had covered the batting with an off-white fabric before putting on the burlap since the burlap was such a loose weave that you could see the batting through it. I decided I liked the fabric better than the burlap so I just took off the burlap. I wanted to try the tufted look since I was considering making a tufted headboard for the guest room. Now I'm not.
It was a huge headache getting the buttons together with the fabric tucked in. Finally I got all 10 done. Then as I was putting them on my 2 year old climbed on the cushion with his shoes on, which were covered in yellow playdoh. As I was washing that out, the water slowly seeped across my fabric, erasing my carefully marked button spots.
I should mention that I know nothing about using covered buttons. I thought using yarn would work. On my second button I realized it wouldn't. And apparently my buttons weren't very sturdy either. The yarn broke and my button popped apart. It was one of those days when I had to just go hold my 4 month old daughter to remind myself that everything was okay!
I tested my first button to see if it was still together well and, nope, the top popped right off.
I probably should've given up at this point. But instead I Gorilla Glued them all together, bought some upholstery thread and needles, and got them all in. Once I had the right tools it was actually not that bad. But not easy enough to want to do a headboard full of them.
So...the finished project (for now).