The colors of eggplant, mauve, purple lavendar etc, keeping in the purple range of colors for the blocks and then any colors you choose for the heliotrope and vine............
Since it is a winter scene - you could even go with Christmas colors, but it would be a bit more selective in what you'd be able to use, since you have the cardinal to think about placing in there also
I also like the dark forest green down to the sage for the blocks - and then add the applique in regular colors.
Another thought is use all frosts of the pastels - let it glimmer in the winter scene!