It took some trial and error, but all the information was already in this post.
I want astray on my impatience and stopped Home Assistant too soon after triggering the purge. @Panzer_V 's advise to wait made me realize this mistake 
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Since it was a lot of reading, I took the time to summarize this topic in a guide
Please let me know if any improvements are needed. I’ll be expending the guide to contain all variations for anyone to migrate