[mtlmtlmtlmtl]

Amazing technical write up. But if there's no cause for alarm based on SMART, I would just do the memtest right then because that's always my goto for weird undiagnosed problems. I find it's usually not the problem, although when it has been I've ended up wasting a silly amount of time on it(just like this case!).

And if there was cause for alarm, I would think long and hard about imaging from the original computer at all. With certain failure modes in drives, just reading could cause more corruption; each failed attempt could lose data.

But yeah, happy you did it this way in the end, because I learned a ton from the resulting blog post!