The buyer requested a transfer from his job to the city where the house is but now the job wants him to start work next week, I told him we can probably let him and his family occupy the property prior to the closing date.  

Learning those things on your own property will then reduce the risk when it's time to buy a property that may not be owner occupied. 

FHA loans are only used for owner occupied properties. and to echo above, there is NO seasoning period for a rate/term refi on conventional loans, and vast majority of loan products that can be used on investment properties. 

I recently learned that if you owner occupy a residence for part of the 5 previous years before sale, and you rent it for the remaining time, you can calculate the percentage of time the property was owner-occupied (and thus qualifies for the sec. 121 primary sales tax exemption of up to $250k for single filers) vs the time it was being rented (which qualifies for 1031 exchange) and claim both benefits. https://hcsequity.com/blog/combining-1031-exchange-with-121-....How does this work for a multi-family?

#2 - Larger 5-bedroom renovation into a sweet rental home Before Pictures (Zillow Link)After Pictures (Airbnb Link)These investors took something that was very boring and extremely residential-looking and transformed it into a cozy retreat for travelers with highlights being adding wood paneling, kitchen renovation, new furniture throughout, beautiful outdoor space with added hot tub and fire pit spaces for guests to hangout and an exciting game room space to occupy guests for hours. 

I did have okay rental income when they were all occupied but definitely could have done better.

I would offer 90% of the market value. if he sells it you with no agents he is saving 6%~ on real estate agent commission and the other 4% is a convenience fee in that he dos not have to endure showings etc. and you will get better pricing on a non-owner occupied property if you put down 25% is compared to 20%.  

This is owner occupied right?

When selling properties occupied it's a challenging task because your buyer pool is so limited to just investors.

A few months later, we received a notice from the lender stating that we no longer had home insurance and needed to secure coverage within a certain number of days.As it turns out, our original home insurance was canceled because it required the property to be owner-occupied.