Okay, so probably a stupid question, but I've never been quite sure of the answer: Can Davith chain the Hidden condition with his ability, allowing him to get it for each attack? Or does the timing work out that you Attack with Hidden -> Spend Surges -> Discard Hidden?

It seems like it's meant to work the first way, but I'm thinking the second way might be the correct one.

Condition keywords give the corresponding condition after the attack resolves.
Hidden and focused are discarded after the attack resolves.

Discarding is a mission/core rule, so it happens first, then the attacker's condition keyword grants the corresponding condition.

For the full story: https://www.boardgamegeek.com/thread/1631857/ability-resolution-order-during-attacks

Cool, thanks. Kind of unintuitive with the effect not happening straight away, but at least I've been playing him right.