I would talk to a good securities attorney like @Jillian Sidoti to see what issue you may need to deal with. 

Whereas you would ordinarily indicate earnest money, down payment, financing and total purchase price... in an owner finance deal you would spell out the exact financing terms such as:Seller agrees to finance $x of the purchase price at y% interest over z years, secured by a first lien deed of trust.

You will likely even have to get a secured credit card to kick start your credit.

Some companies/agents just throw the word Turnkey around to describe a property they have listed on the MLS.

If worse comes to worse, you could just throw a large number out there and make your offer contingent on verification of rehab costs or something like that. 

You can throw it into low cost Vanguard index funds (aggressive) or less aggressive Vanguard bonds and at least earn 3% on your money now.

Who gets to keep the security deposit money under an eviction?

The owner lives out of state and has secured a tenant for the property for the next year (lease expires August 2019). 

I would think that a person that meets a high standard would not have a problem coming up with security deposits.

It can throw a wrench in your pipeline.