I feel step 4. is just a more specific detail of step 2, and the critical tricky piece of their argument is step 3 because that's the step that synthesizes steps 1 and 2. I imagine that the rebuttals would try to show that step 1 or 3 do not hold.
Right, in the conclusion they refer to "means, timing, agent and place" which seems to frame this like one would prosecute a criminal trial in the absence of "smoking gun" physical evidence. If the researchers at the heart of all this were located far from the epicenter of the outbreak, then you'd need to find a good explanation for why it started where it did, which is why I think it should be mentioned as a distinct point of evidence.
No, that’s a misleading comparison. There is no such thing as a “scientific argument” about matters of historical record, because you cannot conduct science on history. Forensics is all there is. It’s just that there is no piece of evidence that incontrovertibly ties the virus to the lab prior to the outbreak, e.g. a leaked research document dated prior to the outbreak showing knowledge of the virus or something.
I think it's more people taking what a court calls 'evidence' and declaring it 'scientific evidence' - sure they both use that same word 'evidence' but they are quite different things and shouldn't be mixed
