Lehigh seems like the easy choice here to me. Ignore average salaries. They provide information about groups, not individuals. You’re a group of one. Research has shown that similar applicants who’ve gotten into the same competitive college, do just as well regardless of whether they attend the more competitive college or a different one. You’ll do very well as long as you don’t let the frat party scene at Lehigh become a distraction. The only advantage that CMU provides is that they don’t offer that same distraction.
Lehigh is a very well respected institution and it’s reputation will hold up after you graduate. Engineering is rigorous wherever you go.