Luckily for us, we only signed a 6 month lease anticipating that we would soon become tired of paying for such a small space that doesn't belong to us.

Contact a local church to assist them.Do they belong to a church?

One is online 24x7 like BP and youtube videos and another essential facet is belonging to a few local REIAs at the same time.  

Whereas in SFH, if you find the right tenant/family, they could possibly be long time tenants. 

My concerns: what if he does not move all his belongings and furnitures?

This advertisement should be in biggerpockets Marketplace where advertisements like yours belongs. 

I just ask that all the departing tenant's belonging be removed and any keys turned in ( I would give the option of a lock change if they felt it needed).If the unit looks good, then I would return the deposit (separate check if they'd like) and do a new lease with just the two remaining folks with first month's rent and deposit.

If you belong to USAA you can do background checks through them for about $15. 

Do you belong to any REIC groups?  

I/we recently inherited a 1/2 acre lot with a small cabin on it, It had all originally belonged to my Mom, but then she suddenly passed away a few years ago and left it to me and my Brother.