Notre Dame is also an outstanding school and right in the centre of Norwich.
JAC is in a building not really suited for a school, with little outdoor space.
CNS is an excellent school with a wide curriculum and really good teaching, lots of forward-thinking teachers interested in developing their own thinking for the benefit of tueir students.
Hewitt is very small these days, dropping in numbers which is one of the reasons the inspiration trust took it over. It is improving.
Yes, the IT is quite rigid in some ways and has some strict routines, also a philosophy based on knowledge, which can translate into rote learning and lines for homework. But schools that do well often attract excellent teachers and my DC, who is at a IT school, has a strong rapport with her teachers, most of whom are both excellent and caring. The curriculum is stuffed with arts, which is unusual for a school with high academic achievement these days, sadly. I'd expect JAC and Hewett to continue to improve, as they haven't been in the trust that long, really.
In NR3, Sprowston would be a contender. I don't know much about it, I'm afraid. It does have some staff who have worked at CNS, which you might be interested in.
Those living in their catchment who don't go to Hethersett often choose wymondham high instead, though I have heard that it isn't as consistently good as it has been in the recent past.
As others have said, you won't get a place at wymondham college unless you pay for a boarder place, unless you live close.
I'd have a look at Notre Dame if you haven't already.