@Cole DeLucas the answer to your first question is a simple math question.

This fee simple unit was available and making $3-4k per month in gross rents.

Simple way to think of it is with the additional principle, would you rather invest it and make "x" (x being whatever return you can generate through RE, stock..etc) or use it to minimize the 3-4% interest rate that's locked.

Simple as that :) 

I only have one property and i live in one half so simple is key.

The more monthly payments you have, the less you can borrow - plain and simple.

I've never known a private lender to provide an amortized loan, they are typically simple interest, with interest only payments made monthly, or accumulated to the end of the loan. 

You can do that with a simple reps & warranties document detailing what the penalty is for not complying.  

The reason is very simple - getting paid a percentage the economic carrott dangeling in front of them in the form of million dollar residential listings is just too big and shiny.Sorry for the long reply, I hope it makes some sense to you!

------------------------------------"Good deal" -- whatever that term means -- is always hard to find wherever and whenever, for the simple reason that a "good deal" for the buyer means that the seller is leaving money on the table and vice versa.In an efficient market there are no "good deals," only transactions where the return on  investment compensates (just) for risk.