1) No, because the electrode copies must be exactly the same as the electrodes. However, if you place another repetition of the electrodes in the central region, and strain that (and leave the copy unstrained) you get exactly the effect you indicate.
2) Stress no, because your strained state is not in equilibrium so it would actually relax back to the unstrained state (unless you include the strain in the optimizer, but I would then still optimize it as a bulk (slab) with the electrode copies as rigid bodies.