Cash out refinance into a conventional loan lets say the equity rose to $500k so since thereis $140k left that gets deducted from the $500k leaving me with $360k for anything else such as another property.

., bookkeeping is a breeze.Also, maintaining good, clean books saves a lot of time for your CPA during tax time; property management statements and summaries are great, but they don't capture all deductible expenses.

The IRS doesn't care if you have leverage or not when you take deductions (unless it's IRA money).

You also get tax benefits and deductions from doing this and get to claim a portion of your home as an office. 

You will still have roofs, AC units, appliances, insurance deductibles, etc on the smaller properties.

I believe the tax laws have changed making interest on a Heloc only tax deductible if you use it for your home or to buy another so there's real incentive to use it in that manner. 

Per the rental income I was thinking of it towards like the AirBnB aspect of it and being able to deduct utilities per square footage that's occupied by tenant.

I think interest is only deductible on improvements to your main home and second home. 

You can deduct any costs associated with the mitigation.

It seems like one of the key reasons is the cap on the SALT deductions.