On the hiring front, undergrad school can sometimes tell you a bit about who a person thought they were in high school, and about their penchant for overachievement. Some schools might help instill different perspectives on engineering and the role of technology. But if you're not hiring right out of school, I'm with you on focusing on demonstrated ability to get things done.
This is actually a really amusing thought. Yeah I could be a manager in 5-10 years hiring current high school kids when they're older. I barely made it through school(failed out at my first shot at engineering) I could realistically be hiring at one of the companies New grads stress out about getting into. I couldn't tell you about ivy league schools without looking it up lol
For all the effort you're making know this: you'll eventually be evaluated by a Gen-X or Millennial hiring manager. We largely don't care where you went to college. We've learned that name recognition means very little. It'll get you a job, but if you're one of those kids who "does nothing" on an extracurricular team, it'll show through on the job. You won't get promoted. We fucking hate micromanaging Ivy League grads who are too scared to take initiative and possibly make mistakes.
Sincerely,
An engineering manager who went to one of the "second-tier" schools you listed.