#1 happens to my DD10 independent of a grade skip. She's extremely social but also is an insatiable learner, and we can't meet both needs at the same time, so she has bounced from public school to home school. There's a kid the same age just across the street that LOVES hanging out with DD when she's in public school, and completely disowns her when she's learning at home.
We also had a near-issue with #2 regarding DD and FLL, because her school allows 5th-6th graders on the team, but she just barely made the age cut-off for competition. The coaches tended to discount her because of her age. But they paired all the kids up to work on specific missions, and luckily her older teammate didn't discount DD, and she actually ended up being a top performer.
