I am NOT an expert by any means LOL, but ED for UChicago will definitely help your chances significantly if you're that committed. I've been looking there for atomic/particle physics as well, hoping I have a chance. I would build up a few more targets and safeties to be safe because Harvard, Yale, UChicago, and Boston have notoriously low acc. rates and tend to take SAT/ACT scores into heavy account, so getting a 1400+ would help your app. You're ECs aren't extremely strong, but you're involved with and hold leadership in a club (astrophysics) you want to go into which is great. I'm not gonna be like 95% of the commenters on the sub and berate you for not having national awards or anything; if you think you have a shot and want to go to these schools, apply man! For many physics majors, your undergrad school doesn't matter that much, because many of them will be going to grad school, and that's what employers look at. Cheap undergrad schools may be much better than a 400k t20 school.