I'll leave the questions to others since I certainly don't have any answers.

I can pass along a bit more about our experience in the hopes that it might help in some way.

DS was in a regular class up to and including grade 3. Our official gifted adventure started back in grade one when his teacher urged us to test him for ADHD. She was having a really hard time with him. School was not going well. Every day she would send home all of the work that he didn't do at school and we would fight over getting it done. It was not fun. His writing was behind and painfully slow. His reading was slightly behind. Everything else was average but at home he could talk about science and math far beyond his age. We figured he was gifted but it turns out we underestimated just how far to the right he was/is. LD's were kind of foreign to us at the time but we figured something was up.

Testing came back with gifted and probably LD (too young to say for sure). The school responded with lots of LD accommodations (scribing, extra time, alternative testing methods, etc) and pretty much refused to do anything for gifted. Things improved a bit and we slowly pushed for more gifted stuff over the next couple of years.

Grade 3 - the school again told us to test because the teacher figured he'd hit the wall in grade 4 without AT and he needed to be officially LD to qualify for that. Tested even more gifted and officially LD.

Grade 4 he moved into a gifted program (cut off of FSIQ or GAI of 140). It has been AMAZING for him. There are a LOT of 2E kids in the program and the more challenging depth has made him actually more willing to fight through his challenges. In his case, it is his processing speed that is super low and it seems to mostly impact his writing. He's now in grade 6 and does the majority of his longer assignments on a chromebook. He's a pretty decent typer now and is able to do smaller writing tasks on his own. He's getting much better marks because he is much more engaged and I also think the teachers there are more flexible and accommodating. DS has also grown and matured a lot in the last couple of years. His writing will never be fast but it has improved a lot. Next year he switches schools (same program though) so it will be interesting to see how that goes. We've had amazing teachers the last few years so hopefully, our luck continues.

Hopefully, the gifted program where you is a good fit for your DS as well. Good luck!