@Matt Buroni very true and good points.

The lack of a second bathroom may be a deal breaker for some buyers and therefore, result in appeal differences. this may be especially true in 2 story houses, where you have to go to a different level to get to the bathroom.

Is that true?

Finding a true deal is one of the hard parts of real estate investing and flipping. 

This is very true . 

I own a rental down in Florida and have done some rehab work on properties but not a true new build.Any advice or information that would be good to learn from (experience, books, etc).

It's true you get a tax deduction for your mortgage, but you also pay taxes on whatever else you decide to do with that money.I would list all of your known investment opportunities, what you think the after tax returns would be, and a risk level 1-5.If paying the mortgage is a clear standout on that list on a risk/reward basis, I would spread out the $60k over a period of time and apply it to principal.You might have other goals like cashflow or reducing risk which might weight towards paydown also.

You need to start by asking the seller what their true financial needs are out of the deal.

We don’t know what transpired and if any of this is even true.

This just isn't true.