How Likely is it that I receive merit-based aid at these schools?

I looked over at your chance thread; your stats are good but Northeastern is not a safety - look at last year’s admission threads and you’ll see pretty amazing students getting denied and WLed. You should consider it a match. You will get some merit there, but the full-tuition University Scholars is for the top 1%-2% of applicants, so is not likely.