Are you selling for $2.4 or netting $2.4 after paying off a mortgage?

Sell price is 2 million so we would be putting 500k down.

Facebook marketplace or even a "buy/sell/trade" group within Facebook could be a great spot. 

I own a Duplex in Florida that I'm going to sell and it is my primary.

How can I find a list of homes that are not currently for sale but that may have an ADU, so that I can start to reach out to these owners about any potential interest in selling?

You can then sell the option to a solar developer, but they too won't execute the lease until they confirm they can develop.

It is also my understanding that several types of loan products including the VA loan and I forget the other one will not qualify if there is any sign of crumbling with the asbestos siding so you may be limiting yourself on the selling side of things if you do not go over it with vinyl.

Living in your home the next 2 years to avoid capital gains tax only applies if you are planning to sell it within the next 5.

Photograph everything before you start cleaning-though without similar photos of the move in condition, you may have problems with some things.Then decide if you want to keep the home as a rental or sell it. 

You're putting in 80k all in, and selling potentially for 115k after 4 months - I think you could find an area with better margin in my opinion.