With 3 minutes to go until closing time, we made it to the Post Office tonight and sent off our I-600A forms and fees - and yep, we attached a cover letter explaining her medical situation and requesting the process be expedited! ^_^ They won't do anything with it until they get our completed home study except perhaps get our (3rd!) fingerprinting appointments set up, but somehow sending that in makes the whole thing seem more real.
We picked up some enlarged photos of Emerson while we were out and hung them on our "kid wall" in the dining room - she fits in so well with the other pictures, it's like she's been there all along. ^_^