Sweet Lemon wrote:
Treat the catapults like normal units for both of these purposes.
I'm just confirming that by "both" you mean both questions in this thread. So...
Spoiler (click to reveal)
a gate with a catapult is considered defended (and therefore may be the casualty of a battle), a catapult counts towards defeating the architect, and a catapult can be taken out by an infiltrator or a charge