I think Naviance scattergrams that have your high school’s data can be very helpful, coupled with a conversation with your school college counselor. If his “green dot” is above and to the R of the pack of Lehigh admits from you school, it is a safety, barring something unusual such as most of the other acceptances have been hooked. Still, have a detailed conversation with your counselor to get specific feedback on the chances at each school he is considering.
On CC, it is too hard to know what your school is like compared to a typical school. There are definitely schools commonly listed as matches or even reaches on CC “for everyone” that our kids have been told are likelies or lower matches (and D21 was accepted to all the likelies and matches so the school assessment of chance was correct across the board). We will see how it goes for D23 but in our case our school and the naviance plots are very predictive for the majority of kids. There are sometimes some surprising outliers who get rejected–however when I have asked the answer has been a generic “there were reasons”, so truly a plot with only GPA and scores cannot tell the whole story.
As for course recs: agree with others, have 5 core courses minimum, and if he wants to have the best chance at these reach-y schools he has worked so hard getting in range for, take the most rigorous load he can handle and keep the grades up. Senior year matters.