Signatures will be hard to sign clearly if the quilt is layered with batting. What about backing the corner sections with freezer paper (which is the traditional way for signature quilts) and drawing lines with a Frixion pen so people know where to sign. You can quilt on the lines later. In my experience you are taking a risk having people sign on a completed top, rather than individual squares, but you gotta play the tune you have been given. Present the top only for signature and promise the couple it will be quilted later. As for the cammo sections I am thinking Cat 'o nine tails and grassy fronds.