The sigmas in frequency domain filters are the frequency sums, yes. DFTTest is a somewhat global sigma, while FFT3D lets you define smoothing strengths for various sigmas. The default in FFT3D is for larger blocking, about what you'd be throwing Deblock_QED_MT2 at. Sigma2 is for slightly smaller blocks, common in poor quantization. Sigma3 is probably the one you want; it's for stuff that is dirt or larger grain sized. Sigma4 is for mosquito noise. I guess something like FFT3DFilter(sigma=0.6, sigma2=1.2, sigma3=2, sigma4=0.4, bt=4, plane=4) should so it.
Contrasharpening is a method of smoothing detail as little as possible on edges, then masking it and applying a difference mask to the unfiltered video. It basically cleans up blocky edges. You can get it
here. EdgeCleaner is probably giving you the error because you don't have awarpsharp loaded. You might also have a version it doesn't like, and tbh if that happened then you get what you deserve for being dumb and auto-loading standard filters which should NEVER be done.
I don't think you need Deblock_QED at all really. I'd just find a lowish sigma and dft nuke it or something. If you really care though, your best bet is probably a two-stage FFT3D followed by some EE or something just to clean it up a bit. I would avoid lsfmod but my reluctance to use that filter is based more on a personal dislike for it than any justifiable problems it has.
I just checked my script, it is 4091 lines long but I hope you don't think I wrote that manually. It was created with YATTA of course; how else would one make black magic so agreeable?