I think the expertise of the other posters is far more advanced than mine, and I think you've gotten good advice. I think it's great that for the present, at least, you've got what seems like sufficient buy-in on the part of her teacher, and I'd make sure that this is transmitted somehow to next year's teacher, hopefully in both written and oral form.
I think it's great advice to nurture her creativity, since it's such a strength. One thing DS has liked in the past is writing his own stories in blank books, filling in artwork as he likes. Maybe that would be one fun way for your DD to continue writing and exploring her ideas over the summer.
As a high school dropout with never-fully-explored math talent (so take this with a grain of salt) I don't think that facility with basic calculation is the most important strength for higher-order math thinking, even if your DD always stayed behind on rote learning-- and this seems to be borne out by your own experience. Maybe she'd turn out to be a brilliant mathematician, but always have to use a calculator. My understanding is that these days, a lot of theorem proving is done by computers anyway. I've read of math geniuses with savant talents, but then there are all the rest of them.
