Oh, sorry. I misunderstood your question.
I would guess that heather Ross owns some of her designs... So she probably licenses out some designs, but is still able to use some for her own printings. Her IP contract might allow her to use the same prints, but only in different colors and fabric types. I'm sure there are designs that she cannot reprint and are the sole property of kokka or west hill or whomever. I think she also has made prints exclusively for spoonflower (from her drawings she does as a hobby), which she has not licensed or sold to other manufacturers.
The hr fabrics I have seen on spoonflower are a combination of previous print/designs and new prints.