However, he has never paid principal, interest, or taken a deduction on the property (he lent his name and credit so I could purchase the property when I was younger).

The dealer pays you interest only payments for 30 years, with the principal paid back at the end of 30 years in a balloon payment.

I only work on commercial real estate these days as a principal broker and investor.

Would an as-is sale of the property cover your principal and make you whole?

I usually have one tenant policy per unit, usually the via the principal tenant on the lease.

You will need to follow up regularly to insure they are staying on track.Back in the old days of rent to own the upside for sellers was in renters failing to buy allowing the seller to rinse and repeat several times keeping the DP and principal each time.

I bought this property for $119,900 and now have a principal amount of $65K.

an LLC can get a loan, but it's more likely that a lender is going to require the principals of the company to apply for the loan. 

Also when you are a principal to the transaction, your errors & omissions insurance will not cover you. 

Interesting, so you have the option to pay off the principal every five years?