Well, your obsession with HMS would point to you wanting a prestigious name on your resume. Emory gives you that far more so than BU. It’s no HMS, obviously, but just a step down and still a T20. People will still be impressed that you went to Emory. Also, prestige aside, Emory is the better school.
You mention concern over money, so COL should be taken into account here. COL in ATL is far more affordable than Boston… not sure if this is already calculated into your numbers. The Emory name might also help you match into a competitive specialty that can help w paying back those substantial loans. I think the advantage in this regard would be marginal honestly, but would favor Emory if anything.
The only real pro you have for BU is proximity to HMS… would he somewhat silly to based your decision on such a lofty goal imo. Unless BU has far better research in your field of interest, I don’t think they have any real advantage to offer you careerwise. Prestige does matter in academia and Emory is the better name in that regard.