There are 2 small children living on the 3rd floor and some very animated adults.   

had  a bunch of issues with the plumbing, so retrospective-- 1 adult isn't bad at all!

If college age and young adults are your target renters, this would be a great place to look.Most of the family neighborhoods are seeing house prices skyrocketing.

"Familial Status" IS a protected class, you cannot use that as a reason to not renew, unless you have in place, and have communicated to them prior to move in, an "occupancy" standard, such as "2 people (not adults, not children, PEOPLE) plus 1 per bedroom" or your local building department restrictions if any.Normally for a non-renewal, and depending on local law, you should provide NO reason.

I have a single family home, currently housing two adults on a month to month lease.

But they wanted to rent a one bedroom apartment for 2 adults and 5 kids because that was what they could afford, and they would 'make due'. 

Since you are not an adult - most states will not allow you to execute a legal contract. 

In the second case, which was my own friends, their adult kids did some pretty decent damage to my house which they (my friends) did not offer to pay for or even cover the cleaning charges, and I very nearly had to evict them as squatters.

However, I rent to fairly responsible adults.

He has a master's degree from the University of Chicago, and has always been employed but has been renting his entire adult life.