(3) is a solid objection. I'm not sure what specifically is meant by "number of variables within a problem that a quantum technology can optimize" but we can use the results of  (Fig 4) test some interpretations. In that experiment, QAOA was implemented on a nearest-neighbor connectivity superconducting processor to solve 3-regular MaxCut.
Probability And Randomness: Quantum Versus Classical by By Andrei Yu Khrennikov is a great book on the foundations of quantum randomness. Introduction to Random Time and Quantum Randomness by Kai Lai Chung and Jean-Claude Zambrini is another work on quantum randomness. Both these books are more focusing on the theoretical foundations of quantum randomness. ...
For such a simple circuit, probably the easier way is to dump it as QASM and read it back.
qasm = circuit.qasm()
prelude = 
circuits = []
for line in qasm.splitlines():
if any([line.startswith(t) for t in ['OPENQASM', 'include', 'qreg', 'creg']]):