Hello,
Welcome to community.
We went through the post carefully. We have also tested in OneNote from our side.
Very sorry to say that there is no out of box feature in OneNote 2016 or OneNote for Windows 10 to achieve what you described.(except question 4 and question 5, you may refer to Bernd's suggestion)
We do understand the inconvenience. Apologize it doesn't meet your requirement.
You bring good ideas and we know it would be great and better user experience if we can do what you described in OneNote app.
Given this situation, we recommend and encourage you share valuable feedback in OneNote feedback community. You may create you new thread, or vote for the following existing threads made by other users who have similar ideas:
Insert option to merge table cells in the onenote. · Community (microsoft.com)
Allow user to rotate objects · Community (microsoft.com)
Add a ruler to the onenote 2016 desktop · Community (microsoft.com)
Add ability to crop images · Community (microsoft.com)
Feedback community is a specific platform to let the developers hear from your voice, know which features are important to you, help improve the product and make it better for you and others.
We appreciate your patience and understanding. Hope you are keeping safe and well!
Best Regards,
Tina
[Updated by Tina Chen MSFT on 1:56 PM, Monday, May 2, 2022(UTC)]