Not sure if one should lock all vacant doors and unlock once leased but this would prevent the hands off management approach as I seek. 

.”, both of these help prevent water from running down the pipe and into the attic.

It really helps prevent me from getting overwhelmed or over frustrated.

Does a lien prevent this type of deal from happening?

Do I have them sign a NDA to prevent them from sharing my idea?

They are crate trained, up to date on vaccinations, healthy, we do preventive measures for parasites, we are very clean and take awesome care of our pets and space.

Get a commitment to sign after verifying with them that they want this and that there are no obstacles preventing them from doing the deal. 

What are some rookie mistakes that can easily be prevented had you known from the start ?

If the unit has been inspected, but not deleaded, you also cannot do any construction or remodeling in the unit, they consider that unauthorized deleading and it will prevent you from ever getting a lead cert.

Then all the above mentioned preventive maintenance is real good.