Wow. There are so many similarities between your children and mine! DS7 presents very much the same way as your DD (adores books, extremely rich vocabulary, loves math, OEs, makes surprising connections, resisted learning to read, and struggled with reading to an extent that seemed unusual for such a bright child) and DS6 is like your DS (except that he learned to read spontaneously later than yours, when he turned 5).
We were quite convinced that DS7 had a LD, likely dyslexia because his difficulty learning to read seemed so out of sync with his apparent intelligence. In part because of that and because of the OEs (and a few other things), we had him tested shortly after he turned 6. There were no red flags in his test results and he tested MG. Fast forward a year and a half, and he's reading quite well though still not perfectly. Everything else has fallen into place, and there are no real problems. DS7 is still more "mathy" and DS6 loves reading, words, wordplay, puns and jokes, but they are both doing great.
With DS7, there may have been a few things at play, including the fact that his extreme perfectionism means that he is strongly averse to doing anything that doesn't come easily to him. And while he could be on a spectrum of dyslexia, it may just be that the mechanics of reading didn't come easily to him and that's that.
Now obviously, there could be something entirely different at play with your DD, and I'm not suggesting that you forget about it. There are others on this forum who will have much wiser advice than I do. But I did want to tell you that there "may" not be anything to worry about, and that it may all fall into place before you know it.
Good luck!
