Neat deck! I want to ask about the Bastion - I can see how it’s on-theme in a deck based around Structures, but it doesn’t seem to have any special synergies beyond giving you a Strategos proc, and the power level is pretty low. How did you find it played for you?
The Build transformation timings are a little weird. As you note, Architect “sees” everything that builds at the same time as it does, but in the same scenario, Vigilator’s buff is always lost on adjacent build minions. My guess as to what’s happening in the latter case is that he buffs the building structures themselves and then it’s lost when they transform, but I don’t really understand how. The order in which the cards are played doesn’t seem to matter.
Some additional trickiness when Build interacts with other effects: If you play a Timekeeper next to a Monument, causing it to finish building, Timekeeper will transform into an Ironcliffe. The same is true if you get a Monument off of Grimes’ Opening Gambit. In the opposite direction, however, if you get a Gate to the Undervault off of Grimes’ Dying Wish then the Gate will “see” Grimes’ death and spawn a demon. The former makes sense following the paradigm that Opening Gambits occur before the minion enters the board, but I can’t reason out the latter.