Hi there,
Sorry for the delay in responding - the holidays + R2 deadlines had us pretty busy! Well first off, you've got a solid GMAT. If you think you can improve it to a 750 for a merit aid bump, be my guest. I'm going to answer the two questions I see above but if I missed any or if you have more, you just let me know, sound good?
First off, there are definitely merit based aid options available to you and yes, your GMAT plays a role. Given your demographic and work ex, I'd say you'd have to be in the 14 - 20 range to get an amount that might be meaningful. But even then, that isn't a guarantee. If the year you apply the schools get a lot of similar applicants who are all relatively good, your chances will drop significantly. You also don't bring anything unique or diverse to the table per se so that'll affect your chances somewhat. Duke I wouldn't count on - you'll see their median GMAT for this year's class rise meaningfully and their latest rankings won't help things. But UNC or Emory or even Tepper or Johnson would be good bets.
As for your involvement, yes, that's light. But think hard about what you did at the Big 4 - those firms require a lot of "involvement" and those communities and thought leadership and whatnot all count!
Bhavik