I then received the strangest message from Nick's phone saying "Hi, I'm Nick's new girlfriend", which I can only assume was an apparent attempt to arise jealousy in me.

@John Mathewson Thank you for attempting to give me an answer though.

I am guessing the buyers strategy of coming up to full asking with 15 days inspection contingency was just to get rid of the other offers, and then they will attempt to get the price down?

If you're a beginner and still learning, you shouldn't be attempting to put 10 houses under contract; weather thats at the same time or in pieces, especially if he thinks you're a cash buyer.I have a seller who wants to sell 16 houses, who knows I'm going to assign those houses to my buyers because I told him I don't buy in this specific area, but I know guys who are looking for houses.

However, I am glad to see some attempt at some sort of control and oversight just the same.

Could the buyer attempt to buy the property in 5-10 years via conventional financing?

She is attempting to buy time with you.Go over to your rental property and post the 3 day Pay or Quit notice on the door. 

I attempted to post it but got an error that posting contact info is prohibited.

I’m pretty handy, so I started tinkering with the system.After many attempts, I fixed the problem and moved a nice family in.

Also, sometimes courts have not enforced late fees in many cases so in the event I do find myself in court attempting to collect they won't refuse to grant the full amount of rent due.