In a pure sub to, the seller has very little legal recourse if the buyer stops paying on the underlying mortgage.Read the specific mortgage, but the general rules are that ANY sort of transfer of ownership constitutes a breach of the mortgage.  

I'm a real estate investor and own a bookkeeping & CFO firm that purely serves real estate investors.

Plus garage, and fully renovatedMy question is should I be looking at this purely based on cost/sq ft, or should I give a percentage value to the property it sits on, then assign a percentage value to the structure itself to figure out the fair market value?

With the pure Fix and Flip calculator, there seems to be a lot less inputs available for this.  

I'm also not sure why she paid in USD given that Oaxaca is not one of the internationalized markets where properties are traded in USD.What Trudy does makes sense because she wants to move to Oaxaca and live in that very house that she most likely carefully selected to suit her tastes.As a pure investment though, it wouldn't make any sense.

I say, with a wife and kids, peace of mind would be a higher priority than pure money.

For a pure investment, I would head much further south.

It's a relaxed atmosphere that's purely networking.

You don't want to supply pure speculation to the bank. 

I have 2 properties and I also house hack my primary residence - my househack covers 55% of my mortgage which is a win for me because there is no way I would find a rental for what I pay in mortgage and the extra income from the house hack is essentially pure cashflow that goes towards acquiring the next property considering i have to pay my mortgage regardless.