Two things: Niche is written by students, parents and teachers with affiliation to a particular school. The basis for ranking isn’t stats or other things you may care about. Some schools have a large number of faculty filling in top ranks, other niche reviews say things which apply to one kid ( or say things which aren’t valid across the board). Honestly, I’d give it zero regard as some of the factors are things which I don’t consider impactful in terms of education.
In terms of kids segregating, that can be a real issue. We didn’t actually find that@ Nobles. Instead, we found kids hanging out by town. And there was a very tiny group of kids who boarded, those kids seemed to hang out also. So, it might be racial but it might be based on commutes etc. Ideally, you want everyone to integrate in every regard. This does happen at many schools. Worst case, is all the hockey kids hanging out only with each other or all the X kids hanging out and the groups are locked.
If they have a parental visit that’s a great way to see things as well. We attended for one at Nobles and got to meet other parents. These are eye opening we attended many for our kids and learned a LOT! Good and bad. Go if you can. And listen to the Head of School. What they say is usually what you will get. Make sure his/her vision aligns with your families.