Cards missing from packs? [Investigating]

DBJones

So, I was looking at the cards the vault says are available in the free packs. First, all the HoU Exclusives are missing, despite being available in HoU packs. They're also not craftable, so I suspect this is part of that. Additionally, two of the cards that disappeared with the Ixalan update aren't available either:
Cancel (AMK common)
Demolish (Origins uncommon)

Demolish is not available in Origins packs either, not sure on Cancel, AMK isn't in the vault right now.

Additionally, the 3-packs you can get from events have a small chance of giving you a masterpiece, but only three of the swords are listed. Seems weird.

//Edited Title -Brigby