Rules Questions thread

Hey y’all, can I get a quick gut check on whether I did this right:

Specifically, I’m wanting to confirm that a Tower does not hit stealthy ninjas from Fox’s Den Students if they aren’t “spotted” by it (since 1 already used it up) but they are “attacking in plain sight” (that is, hitting other units).

For some reason, I have a nagging suspicion tower always hits things attacking patrollers (or any units / heroes?), regardless of stealth / invisibility, and thus I should only have 2 (or none?) ninjas when the dust settles in this turn, instead of the 3 I initially thought.