Here’s an idea: Many of the difficulties fan writers encounter when crafting alternate prequels can be overcome by writing Episode II first, followed by the other two in chronological order.
As I ponder how to write a set of prequels which more accurately fit the tone and themes of the OT, I am struck by the realization that Episode II is the hardest one to do right. There are numerous difficulties that are unique to the task of writing the middle act of a story. It is a large part of why AOTC bombed so hard, because it’s an unenviable task.
If you can make your absolute damndest sure that Episode II is a compelling installment from a story perspective and not merely a series of events which bridge the gap between the start and end of the prequels, yours will be a much more compelling work overall.
I believe a prudent course of action would be to start with writing Episode II, work my way backwards to I, and then jump forwards to III.