You can't imagine how many customers get upset over this. 

Go for a personal note with this slight increase?

You were given a credit, so you have their money.I would not try to collect anything for late return of keys, assuming you had access to the property and they were really out.I highly recommend you find a landlord/tenant attorney and have (pay for) a conversation about landlord tenant laws and customs in your area.  

I plan to refinance this property in a couple years to increase my cash flow a couple hundred dollars a month and then hold onto it indefinitely.If I had the cash and ability to get financing I’d have financed it from the start.

My son is our real estate agent and it's his first deal ( we're his first customer!).  

Lots of people fear the increased insurance premiums, expense and hassle.As to the costs, just talk with a local pool company.  

When the LLC reports the property gain the LLC partners/members will get a tax basis increase in their LLC interest for their allocable share of the tax gain they report, so any cash distributed attributable to the property sold by the LLC should not result in any additional tax liability to the LLC partners/members when distributed to them. 

It will depend on if they will be willing to issue a supplemental loan to increase proceeds.

As a new real estate investor, you should start in your own back yard where you have the advantage of first hand knowledge of the market, the customs, expectations, laws, and a network of friends and acquaintances who can help with advice.  

But I also see how this increases your risk because people know you might not know what you're really doing.For my OOS investmentI Idid purposely look for homes that were in better condition and had big ticket items already done so that I wouldn't have to do them.