Item 1:

https://next.backpack.tf/item/14527891429

Zhou to Xadadada!

11 Keys

Compares from Zhou to Xadadada! and Vice Versa

https://next.backpack.tf/profiles/76561198171759093/compare?from=1717459200&to=1717545600

https://next.backpack.tf/profiles/76561198026129220/compare?from=1717459200&to=1717545600

(Second compare is a tad harder to track, but the first shows that each of the 11 keys moved to Zhou from Xada, and that no other items in that date-range that were removed from his inventory besides the Firestalker went to them.)

Item 2:

https://next.backpack.tf/item/14684627023

Lucifer to Tien

10 Keys? (Compares are somewhat jumbled, managed to find one in which said keys transfer from Tien to Lucifer, but the date-range on the keys appears to line up well within the time-frame that the hat swapped hands.)

https://next.backpack.tf/profiles/76561198978238969/compare?from=1721174400&to=1721260800

https://next.backpack.tf/profiles/76561198076204868/compare?from=1720915200&to=1721260800