Regarding the fire wall of the Chinese, there is a small research on this topic.

As I understand it, a stack of griffins does not attack a fake unit if there is a fire wall in front of it, but it will attack if another unit is placed behind the fake unit, because the computer evaluates the possibility of killing two stacks in one turn and therefore flies into the fire.

I also had a situation where a crystal dragon, instead of killing one peasant behind the fire wall, returned to defend the archers and only attacked on the next turn.

The computer does not seem to notice the "lepeshki" (presumably a specific unit or ability), at least all sources say so, and I have not seen any exceptions.