Thread is tl;dr so I'll just say this:
Spacetime isn't something that is believed in or not; that's the premise of religion, not science. Spacetime is real, but not necessarily in the sense that the table I'm writing this on is: it can't be seen, or felt. It merely is. We can measure it, and its effects- if that's an illusion, then your monk's right, but as far as I'm concerned he's wrong.
As for the probabilistic/deterministic debate, we simply don't know enough about wavefunction-collapse yet to say anything definite. I personally think the notion of a probabilistic universe is a little far-fetched, but **** it, even if the universe is probabilistic, quantum effects go away on the macro scale, so its not all that unrealistic. Bohm (and for that matter, EPR [even if their math doesn't quite work, I'm talking about the idea here]) can't be ignored because Bohr said so- the math itself simply describes probabilities; it doesn't say absolutely that there is no way to determine which outcome will occur given knowledge of initial conditions. Remember, QM describes things as waves which in some sense can be described merely in terms of first-order derivatives and initial positions.
Also, since GR correctly describes a larger group of situations [that we know absolutely have come to pass- i.e. star formation] it inherently ought to be given a deep, deep consideration.