One safety note I have to throw in: If neutron capture is the primary LENR action, then cobalt impurities are dangerous.
This is one of the details that makes the Lundin and Lidgren thesis quite implausible. You've identified cobalt impurities. But if you consider that nearly all isotopes are indiscriminate in capturing thermal neutrons, if what the authors propose is a thing, you will get one very radioactive reactor after it's been running for a while (just like a the walls of a fission reactor). A brief review of the LENR papers shows that neutrons, when they are seen, are recorded at many orders of magnitude below what would be needed to generate heat and that the substrate materials never show signs of neutron activation (which is different than saying they show no activity). In addition, the authors do not give a plausible means by which a lethal number of thermal neutrons will not reflect out of the apparatus and kill the researchers; they do not even seem to recognize that this is an issue that must be addressed in their description, suggesting that they're just improvising. If I recall, they claim that nickel will preferentially absorb the neutrons, which seems unlikely. Even if for some reason only "good" nickel isotopes absorbed the thermal neutrons, you'd still get high-energy de-excitation gammas after neutron capture.
See this Vortex thread for a related discussion.
This is not to say that neutrons cannot be involved; for example, if the tunneling of a neutron from one nuclide to another were to happen, you would not have the problems of free neutrons just discussed, and the daughters would generally be more energetically favorable, and hence less radioactive, than comparable daughters that would appear under a thermal neutron flux. I think you could expect de-excitation gamma photons, however, and an explanation would need to account for why these are not a problem.
I didn't realize that in the bulk of a metal the charge is relatively positive and that the conduction electrons all go to the surface. That's a pretty cool detail to know. Is there a name for this effect?