Next year my rental income will be past the allowable income to keep the supplemental retirement money, but I do not even know if rental income counts against it in federal retirement. 

I agree with Haythem often best just to purchase good insurance (for STR must be STR insurance) with lots of coverage.

Again, shouldnt a roof cost what a roof costs, regardless of insurance coverage?? 

I'm planning to retire in one year but instead of depending on my 401K as my sole retirement fund, I wanted to buy a rental property to supplement my income.

And if you are allowing a business on the property, are you verifying they have the proper insurance coverage, licensing, etc?

I’m supplementing the utilities and insurance as it stands.

Assuming you obtained Owner's title policies when you purchased each of the 5 properties, you may want to contact the title company that issued the policies to make sure you won't lose your coverage after you transfer title.Good luck.  

I do not need lender financing.I know few things I can do: Cover Closing cost, add appliances, etcMost importantly How do I leverage in way I can supplement second investment property with this negotiation in 1-2 years?

They will automatically set you up with liability coverage.

I use American Modern Insurance Group, it’s easy to set up a policy with them over the phone that provides coverage on an empty building.