Jan, You have a challenge indeed!! When I looked at the mockup of Carol45's suggestion I began to see a tunnel leading back into the beautiful focus of the center.. I am thinking if another border or borders in the right colors and shapes that would off set the wonkyness and accomplish the balancing and ease (or take away) the feeling of unrest that the style difference creates and makes it all point back to the beautiful center is the goal here.. I know you can and will come up with a great composition!! Great Creations are made from just such situations!!
I love your concern for the feelings of all those concerned!! Be Blessed!!