1.6 billion? I think that the adjacent spiritual/religious concept quite probably has more than that number of adherents. The AOTC is a more technical notion (and term), which would be unfamiliar to (most of?) those adherents. I think. The adjacent spiritual/religion-adjacent concept might be a helpful route to the answer.
Governmental? No.
Associated with a particular group? For the AOTC itself, I'd say No. But the adjacent spiritual/religion-adjacent concept is certainly associated with various identified groups.

Presumably not, since you wouldn't have described it as spiritual...

Spiritualism? No.
Dowsing? No.

Corporeal? The best and least misleading answer is No. (There is a pedantic sense in which the answer is Yes, because “anything to do with” is pretty broad and vague.)

Solipsism? No—but the audience awakes from its torpor and there is *some applause, mixed with a little laughter* .

On my Marx-Magnet scale^©, I'd probably put the various isms that have been suggested in the following order, with Idealism/Solipsism/AOTC being fairly close to each other. All three are invented by humans but could in some sense be fact.

Marxism ... Veganism ... Hypnotism ... Spiritualism ... Creationism/Btheism ... Idealism/Solipsism/AOTC ... ... Magnetism

Idea about the nature of the entire universe? Yes! *sustained applause*
To do with logic? No.
Relate to death? The best answer is No, though an indirect argument could be made for Yes.

University Philosophy? I'm not an expert in university philosophy curricula, but I'll speculate as follows: the AOTC would show up somewhere in the curriculum but is unlikely to make an appearance in an Introduction to Philosophy subject. The AOTC has an entry in the Internet Encyclopedia of Philosophy, the Stanford Encyclopedia of Philosophy, and Britannica.
Plato's cave? No.
Has anyone said Existentialism yet? No.
Is Existentialism the AOTC? No. (I'd put that more in the vicinity of Spiritualism on the M-m scale.)
Does it entail a belief in predestination? You just had to ask that, didn't you? No.