It may be worth it to contact an attorney to review the history and have them show you the procedure on how to kick them out. 

As soon as it is late, follow your state's procedures- here we can serve a "Pay or Quit" notice in person to the tenant or any occupant over 18, or we can mail it which is what I do since it means I don't have to track down the tenant.  

I am being extremely proactive and shelling out funds necessary to comply with best-practice procedures in the face of a tenant concern in this area. 

Usually, you have to follow a particular procedure to be able to withhold rent.Probably the easiest and cheapest thing to do, would be to just sue the landlord in small claims court.  

Are there any standard marketing tactics / processes / software / to simplify this procedure? 

If anyone thinks they have the expertise to target pre-foreclosures in the face of federal laws, attorneys being in the mix dealing on either side of these matters, Realtors being aware of the legal environment, banks delaying procedures in anticipation of sales or solutions, bank employees reviewing contracts and pending steps, what a seller may do in expectation of a sale and other issues.......well, you just have at it.  

I'm looking to buy a park. I'm very process oriented and want to document everything. It will help the park manager to know what to do, how to do it, etc. Any park owners willing to share what they have put together? ...

Judges don't care about "I made a mistake, I didn't know", only court procedures.

You can ask any questions you have here.For specific procedures, attend a few of them if they are live.

@Annie Graeter, a 1031 exchange must be a sale of investment real estate followed by a purchase of investment real estate in a specific procedure.