Sorry Toby
If you want to get into the detail of the Duff Criteria, you'd need a proper debate over time. You say the Moscow criterios has been dead in policy circles since the late 70s. I think I'll need a bit more evidence than the word of a former RAFR IntO, DFiD CS or an academic study. More pertinently, just going for Options 3a and 3b from the Duff report and dismissing everything else as gold-plating may suit your thesis, but misses the import of option 2 - which was to go after C2 facilities as well. Messrs Khruschev, Brehznev, Andropov and Chernenko were well aware they were personally vulnerable, as did Gorby.
Your "attrition" analysis covers only SAM in the target area. We have forgotten that a working IADS starts killing threats much further out than that. Specifically long range radars of various frequencies and interceptors / CAPs. LO is not a magic cloak as I'm sure you're well aware, it just forces more defensive resources to counter it, through reducing reaction time. But frankly, if your attack run is 1200nm, that's plenty of time to organise.
Your force structure seems to indicate something like 100+ F35 ready to go. Which is a bit of a stretch to maintain from a buy of 138 cabs - something by the way, which will cost additional money that you haven't included in your costs. I don't believe that a UK buy of 138 is in the EPP, but am happy to be convinced otherwise.
As for vulnerability of the dispersed force, I don't have to kill them all, nor do I have to kill them at the same time. I'm just reducing my defensive problem. If I'm in a state that requires me to have my nuclear force dispersed, it's likely that I'm expecting a bit of a pagga with someone. If that someone decides to use non-nuclear means to hit a number of my ORPs, not only is my deterrent reduced, but I have to think hard about whether that strike actually merits a nuclear response. Am I in use it or lose it territory? Article V does not commit the US to a nuclear response as a response to a conventional attack by the way.
HAS ain't all that these days - Granby showed that over 20 years ago. PGM can be mounted on a number of stand-off conventional systems and unless my skim read has missed something you haven't got local SAM defences for your ORP - or expansion of the RAFReg to provide FP against ground attacks.
There's a whole lot of "we won't worry about that" and " it's all gold plating" woven through your arguments, all of which tend to assume out any thought that F35C couldn't actually do the job. All of which re-inforces my initial impression that it's an artifice to provide a policy option (read coalition trade item) that appears to retain a deterrent and strengthen conventional forces, but which can be conveniently dropped once the decision to bin Trident has been taken.
And no, it doesn't
significantly enhance RN / FAA conventional capability....
. What it does is tie a signficant amount of that to a deterrent mission, which will incur a significant training and operational burden. Which reminds me that you haven't included modifying QE/PoW for SW provision.