Yes, delta E & delta t are uncertainties but I was only interested in the maximum possible values. Many people think that the HUP will only show what can be observed but it can also be used to show what is and isn't possible under given conditions. HUP is often used in this manner in studies of new trans-uranic elements.
As to part two of your post, yup I left stuff out. It's been years since I looked at it last and I didn't find any thing that substantially altered the "back of the envelope" calculations. X is still much larger than x.
That is not to say cold fusion as a whole is impossible, for instance there is muon catalyzed fusion that would occur at much more reasonable temperatures. I would also recommend looking at the Tesla table top fusion experiments although I classify that as hot fusion myself.
Your equations were not accurate, as shown.
Thus, they DO NOT show that lattice-enhanced cold fusion "cannot exist".
By contrast, the evidence of 15+ years research
clearly demonstrates it does exist.
Facts, repeated in many countries, again trump
the unsupported unscientific handwaving of the kneejerk-negativists,
as has happened before.
"... after a few more flashes in the pan,
we shall hear very little more of Edison or his electric lamp.
Every claim he makes has been tested and proved impracticable."
[New York Times, January 16, 1880]