I recommend spending some time educating yourself on how to analyze properties to prevent you from making the same mistake again.

OR by violating any laws and illegally preventing them from moving in. 

Tell the original seller so he can be there with a copy of the deed to prevent the placement of the mobile home?

A title report would be necessary to confirm whether or not there is anything preventing a current sale by the owner of record.

However if you want to optimize the STRs, I'm a broker, and our team lead Rory Cummins and his partner created an "Air BnB Wealth Academy," that covers everything from acquisition to staging and photos.Good luck!  

This is to prevent someone from piercing the veil to ultimately bypass the LLC and sue you personally.

Consider using your VA loan benefit to purchase a 2-4 unit.I’m active duty Air Force and purchased three homes with my VA loan benefit.I wish you all the best.

You'll have to ensure it has adequate air flow with the door closed from the ductwork above and possibly the sprinkler piping which is probably dictated by building coded in your area.

Lots of opportunities to stop and prevent it. 

Reach out to agencies in your area (housing commission, Saint Vincent DePaul, etc.) explain the situation and ask them who provides eviction prevention assistance to renters.