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thank you very much for your feedback and for pointing out your paper that I’ve read with great interest. I relize that I should have referenced your paper – I just didn’t know about it before!
Anyway, I think we’re definitely on the same page. Maybe your argument is more general, while my model can help to illustrate your point.
However, I’m not sure to what extent it’s correct that the “causal arrow” is never spelled out as an assumption of Bell’s theorem. At least formally, it appears ecplivitely in what you called “causality” and I called “no conspiracy” assumption. I think many (though not all) people realize that this assumption can be logically denied by assuming a retrocausal influence of the control parameters a and b on the lambda. However, most of them will immediately dismiss any such account as conspiratorial or even absurd.
If my contribution succeeded in adding anything to yours (which it better should, otherwise it would be quite superfluous) it’s to spell out and statistically analyze a specific retrocausal toy-model rather than ‘postulating’ a particular statistical dependence between lambda and a and/or b. I think that this can be quite helpful as an intuition pump.
Moreover, it then turns out that, in fact, \lambda IS statistically independent of the control parameters (unless one also admits lambda’s in the future light-cones of the measurement events). That’s why I hope to convince people that such a retrocausal account need not be conspiratorial (as they usuall assume) in the sense that the retrocausal effects do not need to infringe on the freedom of the experimentalist to prepare a system as she likes.
To be honest, though, I’m not sure if I convinced anyone. Usually, people who are open to retrocausality are somewhat sympathetic to my paper, while people who are hostile usually remain just as hostile even after reading it…