It sounds like your reasons for wanting and MBA are very sound. To answer your questions:
1) I think that now is the perfect tim for you to pursue an MBA. If you wait a few more years, then an executive MBA may ake more sense. But right now a more traditional MBA seems like a good fit for you.
2) Thi is a vaery valid reason to pursue an MBA. In fact, some adcomms might find it refreshing that you're not looking to do the standard jump into consulting or banking.
3) If you're truly just looking for the hard skills that you would learn, then one of those PT programs will suit you just fine. If you're lookng for name recognition, later career-switching options, etc., then you may want to pursue ahigher-profile FT program. This may partly depend on whether or ont you company will sponsor you. If they'll sponsor you for a PT program, then that may make that option more attractive.
4) Assuming you're kind of tied to the Boston area, then consider HBS, Sloan, Tuck, and Yale. Sorry to give you the obvious choices, but thoe probably make the most sense. Definitely don't overlook Tuck or Yale... Very good general management, which is probably what you're looking for.
Scott
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Co-Author, Your MBA Game Plan