I agree that it was a good idea that you backed out. It smells very fishy and I wouldn't trust that Property Management company. Sure, they might not have had professionally prepared financials for 2019, and where were the financials for 2018? Unfortunately, it's quite common to run into Property Management companies that don't pull their weight, especially in the Condo Association space. It's never good to have your investment be contingent on whether the Condo Association PM does their job well. I think most buyers should vet the PM much more closely than most do.
On the rent issue, I think you'll be able to find a rental in the Boston area at a relatively affordable price. The fact that most universities are doing mostly remote learning for at least the Fall Term, I think there will be a lot of landlords that are going to be motivated to fill their units, even at a discount. Otherwise, they could have vacancies until the Spring Term, or maybe even until Fall of 2021. My educated guess is that there will be a large swath of landlords that would take less rent than no rent to minimize their vacancy expense or a prolonged vacancy.