Note that legal and transfer costs are not deductible but can be added to your cost basis.

If you are going to do a HELOC then you must understand the cost of using those funds.  

Cash flow approximately 350 a month.Option 2: Use the cash to buy land to build a 6 bed 4 bath duplex, all in cost approximately 300k/330k. 

I talk to so many people who regret not getting a PM up front because they are having problems or high eviction rates doing it alone.

I (barely) watched some of the podcasts cause BP shows up on my youtube feed when I travel. 

I'm also seeing lots of homes for sale that were used as Airbnbs, so I'm wondering if that along with these numbers may indicate it's an overly saturated market, and if these are signs that maybe I should keep searching for a stronger market, or just a property that cash flows given the average annual revenue?

I would include servicing costs of the loan and licensing costs.

You might have other options to explore to drum up liquidity (HELOC, Margin Loan, Policy Loan, etc) that can supplement your HYSA in the DP.

I did find this deal driving driving for dollars, the realtor of the property was adding his sign in the front yard, I approached to make and offer. we close in 3 weeks.

What I like about multifamily is the splitting of costs.