I personally like the snowman fabric - I think it's adorable! It doesn't take away from the embroidery for me. I do like Bree's idea of adding a red flange. I wouldn't cut the snowman sashing in half, though, because then you won't have any whole snowmen left.
If think children evaluate quilts on their parts, rather than overall aesthetics. The snowman fabric is another element for a kid to be attracted to, if the embroidery isn't their thing. I would keep it simple - trim down the blocks, red flange, snowman sashing, bind in black, and be done!