Wasn't it snafu who asked for definitions? How do we move toward that?
Suppose we equate free will with choice. Then once we release the bowling ball, we have no choice on the outcome. Beforehand our conscious mind says, "I can apply force, torque and direction." So we have free will. But if someone comes along and says, "that force, torque and direction was predetermined by his psychological makeup", free will for that someone does not apply unless they affected it. But how about the bowler himself? If he says, "if only I had applied more torque, I'd have had a strike", then that consciousness, or absence thereof would have limited his free will. He measures his conscious control of the ball. Free will is measured by how much conscious choice one has over the outcome.
Back to the observer. If the observer says, "no matter how hard he tries, he will never become a good bowler", all he has done is bracket the bowler's free will. The bowler is free within those brackets, not free outside the brackets. That is the observer's judgment and opinion. We can in turn judge that observer and pass our own judgment on how that observer was bound by his knowledge and temperament to make such a statement.
So definition:
X has free will for choice Y if X is aware of options and not aware (conscious) of restrictions. X has no free will if there are no options.
As soon as X becomes aware of restrictions he loses his free will for choice Y. Let's check this out using the above example:
Once the bowler releases the ball he becomes aware there are no options. No free will.
Before the ball release he is fully aware of his choice of force, torque and directional play. He is not aware of larger limitations. He has a free will.
The observer is a little different. He knows the bowler has choices within his limited ability, but the observer is more aware of that limited ability. If the observer is a sports expert and is monitoring with all sorts of devices, he knows much more about restrictions. His knowledge removes a lot more options and his claim is the outcome was far more pre-determined (far less free will).