A couple moved in 3 months back, they had some personal issues and apparently have moved out without informing.

As I see more and more of these situations, I'm thinking  it should be mandatory for any new landlord to undergo a training seminar.  

Easier if you just do one person. 

Statistically, 20% down dramatically reduces the risk of foreclosure.TERMS:Interest rates: Some people like to raise their interest rates higher than what a person can get at the bank. 

If anyone is on a tight deadline, I would definite suggest going down in person.

This property cash flows before the ADU.Now im about to graduate college I make more than enough to live on due to having another profitable business with a partner though I have some major personal life changes coming  that will take a lot of my income but I will still be able to save an amount I am happy withIn this position where should I go?

While I am fine renting while I search for the right investment, my dream would be to build (for my own personal home).

But we could not personally afford the mortgage on this place without a renter.

This is since 1) there's no penalty for age so it doesn't matter when you use it 2) the longer the retirement asset exists the more chance it has to grow tax deferred or tax free 3)if you are retirement age then using your personal assets first will likely place you in the lowest possible tax bracket when you start drawing those funds. 

You can not 1031 exchange a personal residence.