I’m looking to setup a billing system for the tenants or use a 3rd party service.

The Qualified intermediary for the 1031 has to be an unrelated 3rd party to everyone. 

Some are more analytic while others will be more personable or social(life of the party).

Wall Street is a rigged Casino but its the only game in town so everyone plays it.

You can hire a 3rd party custodian to serve as a passive processing and record keeping entity.  

Much of the interactions tenants are going to have is going to be with 3rd party vendors.

You want to be able to control issues and learn the ropes while not having to drive far or having to count on third party management. 

I would also make these clear to your tenant/potential buyer before entering attorney review so both parties have the same understanding.

“The solution to most of life’s problems are simple, the hard part is implementing the simple solution.”

The lease says "If the Tenant remains in possession after the Termination date, and the Landlord accepts rent payment from the Tenant, this Lease Agreement shall become a month-to-month tenancy that renews automatically each month until it is terminated by either the Landlord or the Tenant by providing a written notice to the other party not less than 30 days before the date that tenant’s next rent payment would normally be due".