NYS expressly permits those who do not own a car to obtain and register an E-Z Pass account. Whether a non-resident can do so online, or must purchase a transponder at a retail location in NYS is something I do not know. See:

https://www.e-zpassny.com/en/faq/account.shtml

Have you called the PA E-Z Pass Service Center to ask if there is any way a non-owner can register an E-Z Pass account? They might have a work-around.