Here's my plan in a nutshell:-buy and occupy a duplex, renting the other half-after a  year or two, buy another multi-unit property and move in as owner-occupant. 

The easiest way to get started is to talk to all her friends and family member about her being a new agent.

When your tenant moves out if the property sits vacant for even one full month you have used up over half of your allotted budget for vacancies/maintenance/capex. 

I have not had a claim so take that for what its worth.On those policies remember that half of the premium is earned, so if you cancel early (because you sold it) you can only get half you money back.  

Upon execution of the lease (after option expires on their home), they provide deposit, half of which will be nonrefundable if they have to cancel the lease before moving in.2.  

(South Texas is only viable to rent for half a year, to hot for vacation during the summer) Any thoughts on renting properties for part of the year only?

Your 40k return on paper just got cut in half really fast.  

My brother is about to head to college and I was thinking about perhaps putting a down payment on a triplex were he could live, after showing my parents the money he will spend on rent during his 4 years ( about 14400$ since rent around the university is about 300$) they have decided they could pay half the down payment (10k) if I instead don't charge him to live there.

Cash offer for your note is half face value.  

For example, rent out your current place, move into a duplex, and rent out the other half.