Most things in relation to the rental are deductible - Mortgage Interest, Taxes, Insurance, Repairs, etcIf you are unsure of what is deductible, you may want to consider working with an accountant.

Since the HELOC was used for a business use (renovating the rental) you can deduct the loan interest against that rental using the interest tracing rules found in §1.163-10T. 

Many rentals have losses on paper due to depreciation. 

We own a rental investment property in our personal names which we intend to sell and do a 1031 exchange to buy a commercial NNN property.

No problem.. what I did with my ridgeland and Madison rentals and I had bought 12 new builds for the Gozone tax bene's post Katrina..

My CPA was unsure... do you issue 1090-NEC for the difference between 1099-K and 1099-MISC or do you double up the income (i.e. 1099-NEC for gross rents from PM, 1099-K of the net owner distribution on 1099-K, then owner reports double income and puts a line item expense for the 1099-K since 1099-MISC covers gross rents).You need a new accountant lolPM issues 1099-MISC, not NEC for rental income paid to property owners.You would still issue the rental income paid to the owners regardless of the payment method.The Property Owners should add an expense line item on Schedule C stating that income reported twice on Form 1099 to offset any duplicated amount.

@Justin Smith wouldn't do it.Why is he willing to sell you this SPECIFIC rental and not another?

Medium term rentals are the new darling of short term rentals.

The Landlord will verify that the rental is empty of all personal belongings and trash and that there is no damage beyond ordinary wear and tear. 

I'm brand new to all of this and wanted to try to figure out how to do it but when I pull up the rental property calculator it says to upgrade to pro.