Lovely blocks! Regardless of what you end up doing for the border, start with about 2" (finished) border of the cream background fabric, so you ornaments can continue to "float" without hitting the outside edges. Then you can add whatever other border(s) you like.
I like the suggestion of a ribbon border, if you are up for more piecing at this point. Or, if you want to keep it simple, maybe a border of red followed by the holly print. Then, bind in the black.