Thanks for the details.
Hmmm… unique situation that should be complicated but I actually don’t think it will really work out for you in Dropsource. The issue I see first is that you are not going to really be able to tell the table to “unhighlight” the previously highlighted cell when you tap on a different cell because there are no access points to the dynamic list of data from a touch event or anything like that.
The issue is with how I will answer your question 2. If it’s dynamic data creating the cells, no there’s no way to say “unhighlight cell 14” for example. In code, it would be possible but in the Dropsource editor, there’s no point and click way to manipulate dynamic elements in this manner.
I think you need to remove the need to unhighlight from the ux. Perhaps you can tap a cell and do a confirm to move it up or down in the order or cancel. Don’t highlight the cell at all in this instance. Just produce the prompt with the choices.