No way to make the equivalent of the encoding Heisenberg microscope in the situation studied by Sanders.
Basically (z1a'|z3a') is a fixed parameter made by the Kerr cell equally affecting both a' and b' outputs as a local common past cause.
No way to change it locally at a'.
If so, that generalizes Stapp's theorem even to the case of entangled coherent Glauber states without needing to assume that the inner products must small.
However, in that case it's hard to see how John Cramer's device would work - though his argument is intuitively plausible.
Avshalom Elitzur says entanglement signals when ftl violate Second Law of Thermodynamics. Of course some of the people at USD AAAS in a parallel session claimed that.