Regarding reaching out to POI, I would encourage most applicants to reach out. I had professors who let me know they would be retiring during the time I'd be in the PhD program, and they suggested other scholars in the field who might be interested in working with me. That saved me the work of an extra application/the fee. It depends on the institution, but there are also certain professors who greatly impact whether a student is admitted. The institutions where I was admitted didn't have the professors who were the most effusive about my project, but they were the POI who directly told me to list them as my primary advisor in my SOP. So it might not be the thing that makes or breaks, but it has certainly been helpful in my experience.