Please... spare yourself the time and money (and money lost as an attending)... I can attest because I am getting my PharmD this May and want to go back to get MD , because that is where I feel my passion lies... you don't need a PharmD and MD to be a good MD... yes, knowing more drug knowledge from the get go is helpful, but over a few years of practice (and residency training), you'll learn what is appropriate and what is inappropriate drug therapy. Just ASK the PharmD's you work with if you have questions - that's what they're there for and getting paid for... I would say no advantage unless you are a PharmD type, Type A, must know everything, and are willing to sacrifice that time to learning vs. patient care. PharmD/MD isn't like MD/MPH or MD/MBA in that the latter two give you experience that will synergize with your MD training if that another individual most likely will not be able to contribute, if you feel compelled to management or public health... whereas the former will give you knowledge that another person with which you will always be working already has. Your choice on if that is important or not.
As far as the MCAT advantage... again, see above - I'd just take the MCAT and be done with it. If you don't do as well as you had hoped, go to a school with a lower average or a DO that doesn't demand a high MCAT.