One of the roadblocks weir running into is the potential tenant will keep communication and go silent once we bring up background checks.

However, anything that impacts functionality like plumbing, HVAC, or safety issues should be handled before listing to avoid turning off potential renters/buyers.If you’re re planning to lease it, tenants will expect everything to be move-in ready before signing.

The remaining potential issue is their rental properties.

I sent email notification to all tenants the following day saying that this is unacceptable behavior since it can potentially cause a fire and carbon monoxide poisoning.  

You can still find positive cash flow (aka the 1% rule) and amazing appreciation potential.

What is quality of all the tenants on existing and potential?

If you plan to use the remaining HELOC for a DSCR or BRRR strategy, that could help you build more equity, but consider if the current market conditions will lead to higher rates and lower cash flow in the near term.If your goal is to scale, you might consider holding onto your current duplex for the cash flow and focusing on the BRRR/DSCR strategy, which can allow for more control and potentially better long-term returns.

Consider the property prices, potential for appreciation, and long-term rental demand in both areas.

Definitely a good overall real estate market with solid upside potential. 

I'm considering tapping into the equity from either my primary residence or rental property to purchase another rental home that generates solid monthly cash flow.I'm open to investing out of state and have heard that areas like Ohio, Tennessee, Georgia, and North Carolina offer potential opportunities.