Using "does not exist" instead of "equals Unspecified" is the preferred way to write segments like this.  I'm sure there is a better documentation link for this, but check out https://experienceleague.adobe.com/docs/analytics/analyze/analysis-workspace/components/segments/quick-segments.html?lang=en...

As a potential work around, if you breakdown your "Natural Search" by date (instead of just using the line chart), then you can override the allocation model on the inner report to use "Same Touch".  As I'm trying it out, it seems like that only works if you override the allocation model on the oute...

I'm not sure I understand what you mean by sorting each column individually.  It sounds like you want to be able to filter the table based on metric values.  That would indeed be nice.  If that's what you want then, as a work around, you can use the IF calculated metric function to at sort them to t...