You should start creating a pitch deck with a financial analysis / summary and market study to share with people to get them excited about the project. 

The "best market" is less about the market per se and more about the deal you're able to find in my opinion.

Market might be competitive but there is angles to stand out depending on what you are comfortable and able to handle, such as waiving an appraisal contingency, limitng inspection rights and time frames, closing time frames, allowing seller to stay-post closing, taking on difficult tenants, buying properties that might need repairs, etc.

Also Seller hasn’t paid property taxes in 2 years which is a sign the property is in distress.

I would focus on coaching that helps you become a local expert and build relationships with sellers, not try all the BS marketing techniques.

Purchase price: $565,000 Cash invested: $200,000 Current Price: $599K (originally $649K, 67 days on market).

I would never let a client purchase in certain areas of my local market....

How does the middleman (investor) exit out of the sandwich lease option once the investor finds an end buyer to close on the original purchase price between investor and seller?

Off market is really just a marketing term. 

Purchase price: $565,000 Cash invested: $125,000 Listed Price: $585K (originally $585K, 30 days on market).