My accent is very fluid. I'm from right on the edge of the red/blue divide, my best friend's dad is from England and I grew up watching a great deal of BBC to the point where I can sometimes hear regional dialects from England, plus I can note different accents from other countries that usually get grouped in with "British" accents. Aussies, Kiwis, I'm listening to you...
When I spend time in the Ozarks, I sound like I'm from there. When I spend time with my Canadian friends, I sound like I'm from there. Speed, cadence, emphasis, and word choice. So about half of these arguments I say either way depending on where I've been (prounounced like bean, in this case, because I'm not feeling lazy).
As far as the merry/marry/Mary, they all sound the same to me. I say them as the same thing. I can think about how other people might say it and hear it differently, but to me it's all in context. I used to be confused as a young child at Merry Christmas because I had an aunt Mary and at one point asked if she would share Christmas with the rest of us.
I'm in the Tyoos-day camp, not Toos-day. And usually Feb-you-airy. It's a creek that sounds like a creak, unless it's a tiny little trickle, then it's a crick. Yes, to me there is a difference, and it's all a matter of size. But it's always a root like boot, never like foot.
My friend's dad always gets me with VIT-uh-mins and the GARE-age. I say VITE-uh-mins and guh-RAJ. I had never seen the alternate spelling of aluminum until now, so now his pronounciation of that makes much more sense.