One thing that stuck out to me in the Cersei/Tyrion & Cersei/Jaime conversations is Cersei’s motivations. It never occurred to me until these scenes that, based on the prophecy, Cersei believes Jaime would be the “brother” to kill her if she kills Tyrion.

Chains came from Hardhome. Night King brought them because he knew they would need to pull the dragon out of the lake.