I see a lot of good schools on your list for CS and overall. I see quite a few likelies. For computer science, I do not think that I see a safety on this list. Maybe Arizona State might be a safety, but I am not sure. It is a long way to go to get a bachelor’s degree out of state. I am not familiar with Stevens.
U.Mass Amherst is very good for CS. I do not think that it is a safety for CS with a 3.3 unweighted GPA, although a 1520 SAT should help. It is possible, and is definitely worth an application, but I do not think that it is a safety.
Northeastern is a reach IMHO.
Purdue is possible. I am not sure that it is a safety.
U.Washington and Wisconsin and UVA and UMD look like reaches to me for CS.
I might be tempted to add an application to U.Mass Lowell, even though I do expect that your son will probably be admitted to multiple schools on your existing list. If he only gets into Arizona and U.Mass Lowell, I might be tempted to stay local but either is good.