I would not use black with pastel applique on a WOW background. The thread color doesn't have to match exactly. You could go a shade darker to give it some nice contrast. Just MHO.

Thanks for all of the help. I satin st'd the outline of the appliques with the colors in them. I am now outlining the blocks and sashings. These appliques were fused so I didn't need stabilizers.
Darlene