I would try to make the flower thing as an applique right on the bodice of the outfit, with interfacing to stiffen it. Same with the wingy bits, and tuck them down behind the top of the bodice and sew them in place. Make the belt the same material.
Yes, your thread reminded me of what I should use for my avatar. Yes, my mother made it and it's cardboard and I was seven. I loved it.