Downgrade to Deluxe - will I lose all info I've entered by using the 'clear and start over' function?

Unfortunately, yes. That's the idea of Clear & Start Over. However, you will still be able to transfer info from last year if you used TurboTax.

There should be some other option to downgrade since I do not need the feature that I was told I'd need.  If not 'Clear and Start Over' - I should be able to simply downgrade without losing all of the information that I've entered.

This is a terrible feature, and one that is clearly aimed at making $$$$.  Your software told me that I needed to upgrade due to the sale of my home in 2016.   Upon entering all of the info that was prompted for, I was told that I didn't need to include the sale of my home in my taxes since I made a loss on the sale.  Now, I cannot downgrade back to Deluxe without doing my taxes all over again despite not needing the upgrade I was told I needed.  Seriously?