[longtom]

Either case seems to require faster-than-light or instant communication between alternative paths that are being tried out, so the distinction is whether the combination of different paths is mediated by another faster-than-light (non-local) particle or whether the combination is axiomatic to the laws of the universe without a particle mediating it?

[Misdicorl]

No, the path integral formulation does not require faster than light communication. Time is an explicit parameter