They typically want to have the person who physically served the notice and who works for you collecting the rent & interacts with the tenant so that they can testify.

However the previous owner of the property was friends with the neighbors and testified there was a dispute.They ended up settling for some money and an easement onto my friends property.

Rather, they have witnesses who must testify under oath based on their recollection of events.

And testify that those "hypothetical" gains you talked about can be very real from someone who's done it. 

If the neighbors push the issue with the city, the city attorney will file a complaint and set a court date at which you have to show up and testify. 

Next the prior owner needs to agree to testify at any eviction hearings. 

You will need proof, a signed lease or the previous owner at the hearing to testify on your behalf as to what her rent actually was.To win her claim for lost property she will have to provide some form of proof.

Be prepared to get notarized statements from the contractors that were there, or have your attorney subpoena them to appear in court to testify about the tenant's threatening behavior. 

I'll be testifying and Channel 10 did a news segment on it.

I can testify at city council meetings, but the commissioner proposing this doesn't care 2 licks about what any landlord says, and at least 2 of the 4 other commissioners tend to vote exactly the same as this commissioner.