Or if you want to make it more officially, the investor can hire you to manage the STR.

It's not official yet.

Read the official policies here (doesn't automatically apply to all post offices, as the PO must participate): https://www.usps.com/pobox/cus...This makes my PO box every bit as valuable as a PMB at a fraction of the cost. 

That is an unusual number for a security deposit.I would tend to agree put in the appliances - make it easier for a tenant to move in - Looks like a nice enough place, no one lives on top of you and you have a yard for the kids and dog - 1st 3 months rent free with security deposit up front with 18 month lease - I was poor once and every $$$ counts when you can't afford new purchases Great backyard for an illegal global warming bonfire, with the family, on holidaysIn Arizona the owned media have made it their mission statement to make it illegal to have a backyard bonfire on every official federal holiday.

- Notice to Quit - Can't attach because there is too much private information.To ___ And all individuals (tenants, occupants, and subtenants) in possession of the PremisesThe Premises herein referred to in this official notice to quit is located at redacted with a lease agreement commencing on May 26 2020 between redacted. 

What should the official document include to cover myself?

It's not an official ADU/JADU so due to San Diego rules, it doesn't qualify for its own address.

@Sandy Gabin@Jonathan Bombacihttps://malegislature.gov/Bills/191/H4647It is official.

It is very likely that this unit was not "illegal" at the time it was put in service, and having it being in continuous use for 20 years should have alot of sway with the local city officials. 

This signed will acknowledge they have officially left the property.