Those blocks certainly are and need to remain the stars of the show!
All of my immediate ideas are rather low volume/contrast, but I can also see how some contrasting dog show blue and red ribbons would brighten up the piece.
I like the florals in some of the pictures and I would do some sort of "dog park" abstract theme. Pick up the florals, some green for a yard, could even be some sort of snowball block that way, those can really give some movement to a simple alternate square layout. Could be any blocks you want, even sampler different stars or whatever but again, I'd be keeping it very low contrast to not compete in any way with the dogs. You want to see the dogs and then sort of notice, oh hey -- there's something going on over here too. Maybe something like large floral triangles to be like square in a square with the dogs the center, and then a pieced sashing of narrow/wide/narrow bands, where they come together you use a square of the wide fabric.
My big area of despair is with the quilting design. No help at all from me on that for all I could think of 20 things to do in the setting.