Generating two sets of columns by combining information from the first and second set

So I have two original columns with information in each row. Then I created two other columns with edits for each of the original columns. Not all rows for the edited columns have information, but sometimes both edited columns do and other times just one of them does. I want to combine the original columns with the edited columns to have two final columns with original information (for cases where no edits were added in the "edited" columns) and edited information (from either of the two edited columns, depending on whether they both have information - but of course this is only applicable if information was actually added in the "edited" columns).

This sample workbook will give you an idea of what I'm after. It seemed relatively simply, but I couldn't figure it out and I have over 2000 rows of information. Note that I would like to keep the original colours in the newly generated columns: black unedited text and red for edited text.

Thanks (and Im using Excel on Mac, in case that makes a difference).