You can already pick and choose the columns you want for the export of CSVs in mass actions.
The Orders>Reports menu CSV download funfction only contains the the columns relative to the report display so it would be complex adding more columns to it.
The CSV export on the orders listing is meant as a simple one click button. I don't see the point in adding a pick and choose column setting there since in that case, you can do it with a mass action.
Exporting a CSV and sending it by email at a "relative" fixed interval and changing the status while doing it is possible with the mass action system too.
So the points 1 to 3 are already met by what's there. So that means that you don't say everything you need for your CSV export & email function (like for example a filter on the product codes without the having one row per product, etc).
I would actually recommend going a third option:
Having a custom script being built for you which would load the data from the database, generate the CSV exactly like you want with the filters you want directly in the script and the format you need, etc, send it by email and update the order status. You could run such script really precisely, at the same second every week with your own server cron task.
The cost of developing such custom script would be similar to the cost of modifying HikaShop systems to handle your very precise needs, and it could be done by any PHP developer as long as you provide a precise information on what the CSV should contain and what your database looks like.