I'd like to hear more about your journey pre-paid coach. 

I’d require rent to be prepaid at closing and/or withheld fro seller proceeds.

I'm not advocating that accepting pre-paid rent is the best option, but I'm also not convinced that it's a bad option, especially if the lease agreement is buttoned up tightly.  

They simply state the terms of the lease, the amount of the security deposit and any prepaid rent, and the current status of rent payments.

Or you take the risk of something happening down the road (they overstay and, all of a sudden, you can’t just kick them out and must start legal eviction proceedings) Yes, they prebooked and prepaid through Airbnb.

Like row houses or for us houses in SF that are all attached. areas of large lots are not as effective time and distance wise.. on our flyer we had a tear off with pre paid postage they just filled in the little card and dropped it in the mail.

The other item that stands out to me the most is the prepaids/escrows you mentioned for taxes and insurance. $8700 is very high for a $235k home. 

They prepaid for the last month rent. 

make min 3.5% down payment ...ask  seller for  credit to cover loan fees/ closing costs  and prepaids ...conserve  as much cash as  you can  so you can  fund the  remodel / rehab  out of pocket 

It's up to your discretion, and maybe having the mother as a co-signor, securing an additional security deposit or a few months of pre-paid rent would be the compromise made.