Definitely recommend the seller financed buydown as if you refinance whatever the remaining balance from the buydown is can be used to pay down the principal balance of your loan. 

I export large csv files from the MLS for him, I would be happy to do the same for you. 

So yes no capital gains tax, and didn't put any extra principal payment.

I understand this is my responsibility and I filed an insurance claim and the garage is currently being rebuilt as the entire thing was destroyed.

Doing this will give you a lower interest rate, which is why I prefer it to getting a longer amortization and paying extra on the principal.

I wouldn't worry too much about it, if you have a competent CPA or bookkeeper they should be able to review your books and within minutes have a strong grasp on who gets a 1099 (spoiler alert, not every contractor gets one, I'll be annoyed if I get one since I'm structured as an S corporation) and the amounts to report.1099 filings are usually a loss leader for us, so if you're working with a professional make sure you take advantage of them filing everything for you.

So I’m trying to see if I take that equity off the table and re-invest the sale proceeds in another market across more doors where we’ll see better appreciation, OR if we continue keeping it as a rental and work on principal pay down even though the rental price has been coming down and the home is not the easiest to fill because of the above average price for the C- to B neighborhood.Ultimately, my stated goal has been to build appreciation (over cash flow) by acquiring 1-4 doors per year for the next 10 years to allow my wife to retire (or be work optional) by the time she's 50.

But this year, his team is saying I need to file 1099s. 

Under the Corporate Transparency Act, LLC's are required to file a Beneficial Ownership Information (BOI) Report. 

There are also additional costs of operating and maintaining an LLC, like separate bank accounts, annual report filings, tax filings, etc.2.