... and how increase in demand remains relatively constant even while borrower eligibility factors fluctuate, often wildly?

I'm a US Citizen that's been living in Mexico for 3 years. All of my income is from the US, and I easily qualify for a conventional mortgage. The problem is that I don't have a US address for which I can verify reside...

This is not limited to the note and mortgage/DOT but any signed personal guarantee, 1003, all disclosures, and anything else your borrower or closing agent signs.Your lender's instructions, which are typically signed by your borrower and closing agent, should be clear which documents you are to receive as a condition of funding.

Need more information as to your plan.A  co-borrower can make the owner occupant look better but the lowest middle mortgage FICO is used and everyone signs the note.

If I can buy the land and build for 300k and the after build value will be 400 or more then I could borrow against that one and do it again and so on.

So, now back to the definition of "Investment property"TL;DR - lender is helping me to write the letter in a way that prevents fraud AND allows me STR optionsHere is the definition that was sent to me from my lender regarding the definition: source Freddie Mac second Home Mortgage guidelines The Borrower must occupy the second home for some portion of the yearThe Borrower must keep the property available primarily (i.e., more than half of the calendar year) for the Borrower's personal use and enjoymentThe Borrower may rent the property on a short-term basis provided that the property is not subject to any rental pools or agreements that require the Borrower to rent the property, give a management company or entity control over the occupancy of the property or involve revenue sharing between any owners and the developer or another partyYou were right @John Transue and @Keyla Rosario and @Brent Huling I only need to occupy it part time, and can rent it out with no penalty of fraud. 

“For Borrowers with gaps in employment of six months or more (an extended absence), the Mortgagee may consider the Borrower’s current income as Effective Income if it can verify and document that…the Borrower has been employed in the current job for at least six months at the time of case number assignment; and…a two year work history prior to the absence from employment using standard or alternative employment verification.”In summary: if first option doesn't work, see if you can go back before basketball to have your employer complete a Verification of Employment (VOE) for the lender - or round up old W2's (the lender will still want a VOE).

@Jay HinrichsI’m wondering what happens if the borrower defaults?

If you have a fair amount of equity in your home you can borrow against it to leverage in purchasing other assets (no liabilities!!!!).

You are allowed one active FHA loan per borrower.