The question seems really, really silly, but I'll ask it anyway: "If an ability’s requirements are not met, it cannot be added to the ability queue."
So what defines a requirement?
Ensnare should be an easy one: " At the end of the Activation Phase, if you are tractored, you may choose 1 ship in your (mobile) arc at range 0-1. Transfer 1 tractor token to it.
It's really obvious that you need to at the very least be tractored to use the ability. Do you also need to measure the range of a ship before adding to the ability queue, however? If not, this actually changes a bunch of preconceptions that my Facebook group just had.
If a requirement is defined as something that is in an "IF X then Y" clause, then this could mean that combos such as Ketsu and Old Teroch still works. Old Teroch could add his ability to the queue, knowing that he is only allowed to measure to any number of target once his ability is reached in the queue.
This FAQ needs a lot more concrete examples, I fear