Tenants are paying principle of $1272 a month (15K a year).

I am so furious on principle about this.  

This monthly payment means principle and interest: the higher the interest, the less loan amount may be approved by that lender for your buyer.Seller & Buyer Agent duty: Let both the sellers and the buyers know that the interest rate is one of the major factors that impact the speed of property transaction.

If higher interest, maybe it could even be interest only for a period to keep his payments manageable and he'd have equity before any principle pay down. 

If you have worked for yourself for 17 years, then I 'm sure you have provided service to people, you have customers who trust you and value your work , your work ethic, ... etc.

I assume the principle issues are potty-training and chewing for puppies, and potty-training for kittens.My question: For a cat or dog, what minimum ages will you accept?

I guess the same principle applies, that I will begin depreciating the first payment in 2017 and second payment in 2018. 

The first as mentioned above -- equity add through the principle portion of the loan payment -- and I am also sending some extra payments to the first position loan as an extra equity insurance policy and pay off my primary residence faster.

@Kagan Sharpe  Ethically, no problem. 

So if you have 100k out, at 12%, you're paying $1,000 in interest per month with no principle pay down.