I have not heard anything back after the Skype interview, but I am sure that follow up news will be coming this week.
I was contacted by both my POI and another PI I had not mentioned in my SOP. I think it's not too entirely surprising, because the PI I did not mention in my SOP who reached out to me was still in the same research area/topic I had mentioned. I think if the PI students mentioned in their SOP are not looking to hire more students this admission season, similar-topic PIs may be interested in those students.
I will keep posting back results on this forum on Penn!