I read a lawsuit (OH) where a jilted buyer caused the seller and subsequent buyer all kinds of grief and actually ended up with the property.

You could become part of her lawsuit, inadvertently, by ‘helping’.  

This class action lawsuit may change your mind

Most likely the state where the property is located is where lawsuits would be brought if they are something for personal injury like a trip and fall or something of that nature because the “cause of action” arose in that state.

I was also looking into a SFR with the ability to build a (I can't remember the acronym) mother in law suite or separate dwelling.

The benefits of it from a legal standpoint is that it gives you an extra layer of protection when it comes to a lawsuit.

I understand that forming an LLC can be a great way to build good business credit for purchasing investment properties while protecting yourself personally from any lawsuit that could come up, on top of other tax benefits.1) Once you form a Delaware LLC, what are some of the fastest and best ways to build business credit with your new tax EIN?

Owning paid for property is foolish, just paints a bullseye for lawsuits. 

You may open yourself up to a lawsuit for them to compel you to close.

If you want to get them out using the courts, you file an ejectment lawsuit in circuit court. it can be timely and expensive, but most times you are able to get a summary judgment.