Definitely not a skill in my wheelhouse, but yeah it would be cool!
I use heads from other figures on Dawn all the time, and I call it "composite" figure. Just parent a head, and boom, as long as I match the materials, nobody will notice them blatant neck seam. But in this particular case, it could be possible to mix the morphs and keep the head. The challenging part would be to reconcile the skeleton differences, and that's where animatable origins would come handy. However, I don't think the tiger uses the same UVs as Dawn, so the materials won't match.
So even if a morph would be possible, compositing might be the way here after all.