2. Who attacked Kaden's old pack? Why? Is this linked to the attack on
Gabriel's old pack when Marx and Cami were there? I think the timeline
puts them at about the same time.

The timeline does put them there. But Kaden's old pack being attacked, is/was a way to find Kaden. Remember he's been living as Reese since he walked away from them. The Elders are looking for Kaden and Kieran and the others that escaped. They were the success stories of R43.