Main 3 points I determined was 1) what the sale price is (principal) 2) what interest rate you want (and what is legally acceptable) 3) how long of a term you want the contract to go for. 5/10/15yrs etc. 

Had I done a duplex it would’ve most likely only broken even with my PITI (principal, interest, taxes, insurance)

As a general rule of thump judicial foreclosure states, which require a lawsuit in order to foreclose, take anywhere from 9 months to two years to complete a foreclosure, during which time the debtor can pay off the mortgage by paying the principal, outstanding interest, late fees and legal costs of foreclosure.

I have 7 commercial properties but with conventional loans that are 20% down and amortized over 20 year ( interest and principal ) .

Many of the unsecured PLOCs that I have all ask for interest only (at around 10%) PLUS 2% of the outstanding principal balance. 

., principal paydown), as well as projected appreciation at time of sale? 

You also make the same $600 payment on Loan 10, except you also put all your cash flow toward the principal (you do should make sure the bank knows explicitly that extra payments go toward princ, not future interest, they're tricky sometimes).

The home we bought was being renovated for my daughter as her principal residence.

You will need to know the current principal balance, the amount of money needed to bring the loan current, the amount of rehab the property might need, the monthly mortgage payment amount, and the potential ARV of the property.  

Roth IRA principal can be withdrawn tax and penalty free....just not the earnings.  401(k) loans are similarly allowed and not taxed or penalized.