Thank you for the detailed explanation. At the end of the day, it is all about empowering the non-technical folks to do content changes, so I completely understand your question.
It is definitely possible, so let's see how we, the developers, can achieve that for the non-technical users.
Before going to any sort of instructions, I want to ask you why don't you create such a Dynamic Module that represents the structure you are requesting? You will have all those items managed in the backed of Sitefinity and you will achieve that requirement in no time. Please check the example on the link here
This is really aligned with the best practices and you can configure really slick UI for the users. Is there a reason for you not to choose that approach?
Speaking on your question though, I am afraid it will take considerable time for development. You would need to create some dynamic UI in the widget designer that allows to add the items as you have requires. I am thinking of using something like the Kendo UI list example, so you can add more items to the collection (link here
In your case, you would need to add this to the next level to reuse the Image selector and all the other fields and hence the complexity - it will need a lot of client side logic for the dynamic UI, but it is definitely possible and I have seen some developers doing something similar.
Please review the options and let me know on the direction you want to pursue here.
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