More values issues

I've been struggling with the values in these 3 paintings for a while. If I can't resolve them soon I think it will mean abandon... which will be sad as I've become quite fond of my skeletons. The problem is that the skeletons are quite light in background. However I've tried to avoid darkening around them. If I had known that I needed to do that I probably would have cut them out and collaged rather than left them in one piece and need to paint around and in between their ribs.

 

The poor pennyfarthing is almost indistinguishable from the background colour in this black and white version and I think it needs far more pop. I've darkened around the had of the skeleton with the daschund and then spent ages using white to lighten the other two. I really don't know which way to go. I only know that they are unsuccessful as is.

Done