If they try to argue/debate, simply say it isn't up for discussion. 

The newer smart-*** ones will argue with experienced builders over stress and load points and stuff they have no clue about.

don't argue with the insurance agent. 

So needless to say that I need the rents coming in. my problem that I have is that one of my first tenants brings his girlfriend over every night and they argue by slamming doors and disturbing my other tenants.

One might argue that she is asking for a reasonable accommodation (and hard to argue that it's not reasonable if it has been happening for 20 years with no major problems). 

Right now we are on the high side of things.  2 years ago, we were on the low side of things where money was cheap, and cash flow was easy to be had.Some will argue to go ahead and buy now for a 'no cash-flow, future appreciation' play.  

Most experienced real estate investors would choose Offer #3 in a heartbeat (In fact, I'd argue that most sellers would accept #3 even if it were a lower offer price than the others!). 

Then file your suit.In court you'll have to argue your case. 

Arguing never works.Get a good attorney that specializes in landlord/tenant law and accept that it will at times cost money to have them deal with things.

Really difficult for them to argue once a baseline for move in is established.