Totally agree with you about the use of "disability", but, in the world we live in it IS a disability - using the social model of disability. Children with ADHD are frequently labelled as "the naughty child" in early years settings, "the disruptive child" at school, and "not really what we are looking for" when applying for jobs. From an ADHD person's viewpoint, society is cruelly disenabling, to the point where basic needs such as friendship, education and work are 100's of times more difficult than they should be.
As a "hidden disability" there are difficulties around the judgement of others too.
But the difference between classroom and home is that your home won't be a hostile environment!
A couple of other thoughts.......
-your potential daughter may have all sorts of other difficulties mixed in with ADHD. Or turn out to have the other difficulties, but not the ADHD, or ADD without the H. Dealing with all the professionals involved can be more stressful than parenting the child! There are often long delays in diagnosis; no joined-up services; support that is too little, too late.
-the classification of ADHD changes from time to time in terms of paperwork and support mechanisms. At one time it was SpLD, but then changed to "behavioural issues" ignoring the underlying needs. Within adult services it falls through the gap between learning difficulties and mental health.
-also thinking of adults with ADHD, did you know that there is a strong link with bipolar. I haven't seen a recent figure for the percentage, but I think it's high, so worth considering how you might manage that risk in due course.
My daughter is now in her 20's and her ADHD symptoms, which were classed at the severe end as a child, are much more manageable as a mature adult. She still keeps some of the bounce and liveliness and her "in the moment" attitude. As a child she made other children look like cardboard cut-outs! She is probably the most courageous person I know.
Good luck with your meeting, hope it all works out.