Oh lame. My JSON merger is only "merging" the top layer, so:
{ "Animator" : { Tint : { R: 255, G: 255, B: 255, A: 255 }, Scale: 1.0 }, Health: { val: 100} }
merged with
{ "Animator" : { Scale: 2.0 } }
gives me:
{ "Animator" : { Scale: 2.0 }, Health: { val: 100}}