@cfscollege My D17 had similar credentials as your DS. And she is a ChemE major!
She has 2 schools from your DS’ list. She got $29,500/yr from Case but waitlisted at Lehigh. She was very upset with her result with Lehigh as she was hoping for their full tuition scholarship. She visited; talked to the admission lady when they visited her school; email-communicated with them during application cycle. I think she has the most demonstrated interest with Lehigh than all her other schools. She emailed the admission lady and asked why she was waitlisted. The lady emailed her back saying she was in deed at the top of their applicants pool, but they can’t admit everyone from the top. She basically told my D they practice yield protection. So be aware since your DS will be at the top of their pool as well!