Yikes. The main thing I get from that is that is going to pay to be cautious in taking positions on this topic.
This calls to mind how DeWitt comments that Lucretius seems to contain very little information on this subject, but that may be because Diogenes Laertius is the muddy one.
Maybe DeWitt is correct in pointing to the Velleius material as the best way to unwind the issues.
Very complicated and unclear subject.