Things have gotten progressively worse with the final straw being that he/his crew dumped sink/trash/rugs/mattress/furniture in the backyard, right next to the house, after renovating a unit.

Or do you show it to prospective tenants before you clean it (with used furniture, garbage bags, smells, and overall suggestion that the landlord may not give a damn about the upkeep by any tenant?)

Even though it's not big enough, people will use it for their children with some sleeping pads and/or a crib.

They have two younger children in the bottom unit. 

Would love to have freedom of time to enjoy my children grow into wonderful people themselves and not miss all the milestones along the way which is why I am so interested in REI.  

Think of how a house looks after moving all the furniture out.

Seems like for each place you need $1500 for first month rent, $1500 for security deposit, and $5-10k for furniture.

The upper unit usually does not have acceptable access, wide enough for furniture.  

And whether you want(ed) your real kids out of the house as fast as possible, you want these quasi-children to stay as long as possible.So, focus on providing proper guidance and expectations throughout the experience.Hold them accountable and yourself equally so.Okay, so there you have it, the 3 keys to getting a tenant to stay long term:Price the unit aggressively to incentivize them to stay.Provide Quality Maintenance (and finishes)—take care of problems to avoid unnecessary disturbances and have the quality of finishes in the home commensurate with the price of rent.Provide Quality Management—Be Responsive, Make your home easy to live in and your rules easy to follow, and be a good parent.Thank you for making it this far.

The Ceiling slants downward to the sides of the room, the appraiser only measured to where it is tall enough to place furniture.