"How does this sentience operate outside of time (assuming that Einstein was right and that past, present, future all exist at once)?"
I have never heard this theory explained satisfactorily. Why would past, present and future coexist? I have a sensation of the passage of time: if I jump off a building, I won't hang there indefinitely, nor will I strike the ground instantaneously. So there is a causal process to the universe. How can this possibly be an illusion? An illusion experience ITSELF requires causality and independent moments of time to exist. Is this after-the-fact reasoning? Yes, but I don't care. :)
The prospect of an unaware God I find more terrible than NO divine order. I don't want to make an argument based off this emotional response, so I'll just stick it in as a side note. The idea of an existing but unthinking God sounds to me like a dead pilot in the cockpit of an airliner loaded with screaming passengers. It fills me with a deep, yearning sadness.
"there are intelligent beings in this universe whose actions and thoughts must also conform to the consistency of this mathematical order. So how is this determined? That is, what if you happen to be the first person in the history of the universe that happens to have a thought that would throw the whole mathematical order into contradiction? What prevents such an occurrence?"
What prevents such an occurence is that nothing CAN occur outside this order by definition. I've made the argument before that if you could acquire enough information at the start of the big bang, the position, velocity, and properties of each particle and wave at the start of time, you could predict the exact course of each particle throughout eternity. Humans are not exempt from this determinism. So, nothing can occur that contradicts the universe's order because the order is inviolable by definition: it's all cause and effect.
"The answer, in my view, is that we are fully part of the whole 4D object which means that the actions of the universe are directed for a specific outcome which even includes our actions as well (i.e., teleology)."
Personally, I think the word "directed" directly implies sentience and purpose. The "specific outcome" of this universe is to expand into infitity forever. Just because the future of the universe is predestined does not make that future purposeful or directed.