First of all, congrats on your GMAT! That 700 is a life saver, esp given your story about your undergrad performance. As for "applying lower" from what you have written it doesn't seem like it makes any sense, because the only two schools you could reasonably afford and would want to go to are Baruch and Binghamton. So you simply apply to those and give it your best shot.
And now to take on your specific questions:
1) Are my target schools realistic with my less than stellar credentials? If not, are there any comparative schools that I should consider in terms of MS Accounting program reputation and cost?;
I think if those are the two schools that fit your needs (I assume in state tuition has something to do with it) than those are the two you should go for. PErhaps Stonybrook also has a decent MS program?
2) Do schools give any preference to the alums? I would like to attend my alma mater (Binghamton); and,
Often yes. But you will definitely have to convince them that this time around you are gonna take it more seriously.
3) In terms of personal statement, how personal do I get? My brother's death have contributed significantly to my decision to attend grad school but I don't want to come across as if I'm begging for pity points.
You can. And it depends on the question. Obviously this isn't the main point of the question (rather your GOALS are) but if it's important for you to explain something, why not? And you can go it without "begging for pity" or even coming across as melodramatic.
Other than that, and related to my point above, I think it's also important for you to come up with some solid and specific goals of what you want to do after you graduate.
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