For example, if I only held the loan for six months, I would only pay half of the total annual interest that was due.Additionally, the investor was always in the first lien position, with a mortgage recorded with the county at closing.

I found the local county recorder of deeds website.

They handle:Monthly Payment ProcessingEscrow for Taxes and Insurance: They ensure property taxes and insurance are paid, which is essential to protect your interest in the property.Record Keeping: They also maintain records, which can be invaluable if any issues arise during the term of the loan.ConclusionGiven the details of your property and the $200,000 sales price, a possible scenario could look like this:Down Payment: 10% ($20,000)Loan Amount: $180,000Interest Rate: 8%Amortization: 30 yearsMonthly Payment: Approximately $1,320 (principal and interest)Balloon Payment: Due in 5 or 7 years (this allows for refinancing or payoff while giving you some flexibility).These terms are flexible and can be adjusted based on the buyer’s credit, down payment size, and negotiation.

It's going to challenging as a first time investor trying to convince someone to lend you money with no proven track record. 

Still record low inventory, low rates and a ton of demand.

As you do more deals and have a track record, you will be able to retain more of the deal.

For both tenant and landlord peace of mind, the property had an extensive video surveillance and security DVR system already installed by the prior owner, which covers outdoor areas and indoor common areas and records 24/7/365, as well as sensors for excess dB noise levels.

Regardless, you are putting yourself at risk of getting sued by trying to market a property without a real estate license, a valid listing agreement, or being the owner of record. 

The clerk of court doesn't handle the tax deeds, except for recording them. 

I've had several bids, all much higher than the original, unrealistically low contract price, with of course a lot of variety in the price, experience, and track record of various builders.