Yes, your house is sitting empty but how long till they miss a payment then you have to go through the processes of evicting 4 kids and 4 adults.

They are adults and know the process.If they haven't paid by the 9th, I'm serving a 3-day Pay or Quit Notice through the Sheriff.If they still don't pay, I file in court and they receive a Summons from the Sheriff.That's it.

I'd change the no excessive late payments to no more than one late payment - otherwise, it's too subjective.You can add lots of other things like - smelling like smoke, rude behavior, unruly kids, bickering adults, adults yelling at kids, showing up with rude friends, filthy vehicle, having someone other than applicant who is doing all the talking, showing up late, sounding drunk when they leave a voicemail, not filling out application completely, asking for lots of changes like new carpet or paint (they'll be difficult to deal with), tenants who never ask where the laundry is or look to see how big the closets are or ask about parking (they are desperate to take anything), not bringing documents when they said they would -- the longer the legal list you have, the better. 

I also live in Renton, and the rules are most likely the same in King county anywhere, but single family home is for up to 4 unrelated adults. 

The tenants are an older couple with an adult son who is disabled and in a wheelchair. 

I don't take cosigners for grown adults.

Then as was mentioned, personally speak to the adults who live there.

Beyond that, no adult wants a grown-sized babysitter coming to check on how they live.

My intention was to give the apps to all adults in a household if they are interested in the property.

If college students are going to cram 5 full-sized adults in a 3 bedroom/2 bathroom home you'll get a lot of wear and tear, parking is a pain, noise complaints in a family neighborhood, the occasional kegger, etc.