Oh no not another free will thread.

[Edwardo Piet]

Freely in libertarian just says that it's a choice, not causal determinism.

Under libertarian free will, it is possible that nothing determines the choice one makes. Logically incoherent, but that's the free will the typical theist believes in.

Prior to receiving the tape from the future, Bob can't know what Larry is going to choose, which rules out causal determinism, no?

Not necessarily. The only way to rule out causal determinism is to say that choices can be made randomly, which is not what you're assuming here. Larry still chose what he chose for a reason. And Bob simply observes that choice in advance.

No one has to know anything for causal determinism to be true. Knowledge requires minds and even minds don't have to exist for causal determinism to be true.

All causal determinism means, in the philosophical sense, is that every single thing that happens in the universe has a cause. That can be true with or without minds.

The idea of an omniscient being is just one way of showing how if you will definitely do X then it of course makes no sense to say you will not do X.

No omniscient being is required of course. No knowledge is required, of course. No being is required at all, of course, for philosophical determinism to be true.