Re: cot-caught merger not official?
For me, talk and saw are the same sound as caught, but cot is different - it's the same as hot. I'm from New York, and the only thing that would tell you that is when I say coffee as cawfee - more like saw and less like hot. And Dawn and Don are completely different as well.
And as for the accent of the capital being "official"? God no! I'm not sure I'd know a "Washington" accent if there even is such a thing but no one concsiously tries to emulate it. Baltimore is just of the road from DC, and it has a weird accent all its own.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.