I don't think it was every Frey. In the toast she made a comment that she ordered every Frey that meant something to her to present. We don't know how long she posed as Walder, but I think she did long enough to find out who participated in the Red Wedding. I'm thinking that any Frey that was involved in the murder of…

The council was Perlmutter's thing. It's still around, but has much less power. Perlmutter was kicked out of the movie division during Civil War. So, he had some influence over that. I'm not sure where Dr. Strange or GotG2 were in production, but I don't think he had any say when it came to those movies.

I've been assuming that someone at NBC has been calculating the ages of all the children ever since hearing about the Magnum PI reboot starring Magnum's daughter.