[DannyTN]

you have yet to explain how a hypothetical demonstration that life-from-nonlife is impossible would falsify common descent.

Didn't realize I had been asked to. demonstrating abiogenesis is impossible doesn't directly falsify common descent. But it does undermine the uniformitarianism and naturalism philosophy underlying common descent.

If a designer, ET, or God was required to provide the initial life form, then it is not only plausible, but likely that the designer, ET or God would mold higher life forms into what they wanted.

Thus, once God or a designer is considered as any part of the solution, it becomes logical that the Cambrian Explosion is attributed to that same force rather than natural selection.

[Dimensio]

But it does undermine the uniformitarianism and naturalism philosophy underlying common descent.

This is your problem. You think that evolution is based on some kind of "philosophy". It isn't. It's based upon the fact that it's the best explanation for the current evidence.