First of all, congrats on your amazing GMAT, this beautiful score is only a confirmation of the excellence that you have shown until now. So really great job there. As for your split, I wouldn't worry about the low quant. First of all, it can matter SOME, but it's far less important than the actual score, and when you are at 750, it obliterates it.
You write:
" Hopefully, the adcoms will notice that I was doing graduate level math work for my last publication and not place much weight on this quant score."
Now, I' not sure you NEED to (will depend on what else you have to write), but actually don't expect them to "notice" anything you don't tell them. So ultimately if this is a concern you need to address, you may want to write it in an optional essay. But only "may". With a 750, defining your "low quant" may only seem ridiculous, given your score.
Your goals are better now, also, not so much because of the "lateral" change, but more because you seem to have made them more precise and concrete, which strengthens them.
There you go!!! Now, all that's left is your actual applications.