Thanks for reaching out. Sorry this post got missed somehow - I hope that even a delayed response is a helpful response.
Your whole plan of attack seems very much on point. I am personally a big proponent of dual degree programs, not just because of the ROI (such an MBA specific way to think about things), but also because of the holistic learning and development that takes place when you use different models of instruction. Adding a Kennedy School experience to an elite MBA, for instance, is going to have an exponential effect and likely make your time in school 3-5 times more valuable rather than just twice as good, via double the degrees. JD/MBA programs are similar, as are MBA/MPP combos. I'm sure there exceptions, where there are diminishing returns for the extra time and money, but considering that the MBA is the least "academic" of the big masters programs, adding a really thoughtful course of study can really open the mind.
And, of course, it can have real "paper" value as you move forward, but I truly believe that is secondary.
Now, as for how to approach it, the key is to really make your case for why both degrees are necessary. We work with a lot of dual degree candidates (especially for the HBS programs - JD/MBA, and HBS/Kennedy - and for the extremely popular Kellogg JD/MBA) and what is often missed is that dimension of really spelling out why the secondary degree is so critical. Many candidates approach it just like an MBA application and forget to showcase the need for the accompanying program. This probably seems like common sense, but you'd be surprised how easy it is to fall victim to a "pure MBA" approach, especially since so many joint degree admissions processes piggyback closely to the MBA process.
Be thinking about how your goals, interests, learning style, and perspective (the teaching you will be doing to and for your peers) lend to the joint degree. If you do that, you will be able to showcase proper career goals, transferable skills, key program traits, and - most importantly - nuanced understanding of program DNA. And you will be off and running.
I respect and appreciate that you have shortlisted your schools and you don't want to compromise that list - rather waiting and reapplying if need be. I don't think it will come to that, based on your profile, but you are wise to be selective and bank on your youth.
The only thing I would say is open your list to include MIT and its dual program with Kennedy. Same city, incredibly elite institutions, and what a great combo of learning opportunities. Here's a link: http://mitsloan.mit.edu/mba/program-com ... -programs/