About the friends- just stay true to yourself and you will soon see who the true friends are. When we had our son tested and pulled him to homeschool after K last year, I expected a backlash. Instead, I was surprised by how many of my friends were not surprised by any of it. So many people said, "Well I could have told you that when he was one!" Best of luck on this wild ride!
When my son was skipped he was in third grade one day and the next day he was moved to fourth (about a month into school). When he arrived at school the day he was moving to fourth he walked up to one of his classmates in front of the school (I was there because I had to see the guidance counselor) and told him the news and the kid said (with big eyes) Wow! That will be great for you!
So parents know and I believe that the other kids know too. Luckily we have a very accepting and nurturing school culture (as much as you can have in this current test them to death era).