Wow this thread filled up fast!
I think you can sous vide in your BK just fine. As long as you pre-heat the kettle water, even with the bag sitting on the element, I doubt it would melt. That said, I would keep them off it if possible. I've weighted bags with river stones, but spoons work too. A little kitchen twine and you can hang them off the side, tied to the handle. Easy to pull them out.