Frankly speaking, you have a very slim chance to get admitted by phd in b-school(top 50). I recommend you apply stat phd first and then transfer to b-school with stat master and strong recommendation from american professors. the average year of phd stundents in b-school is around 26
I am sorry about my last reply. I take b-school phd roughly equal to finance phd and now I realize there are several departments in b-school(even stat, ft), so what I said concerned finance deparment only.
I think econ master will be best choice if you don't need financial aid otherwise pick phd degree. And also, the choice should depend on the rank of the school, overally. for example, you should accept stanford stat instead of pen state econ. Last, the b-school in your chosen university is tremendously important because you can think that as a backup. (taoci with professors face to face in the first year of your ma study)