Then, be aggressive about negotiating with the seller two options:1) Property vacant at close - you pay original agreed price2) Property NOT vacant at close - you pay orig price LESS an aggressive amount based upon above.Great advice - you should be embarrassed about how low the offer is you make!

My credit is 790+. 

@Khalid Bryan another option if not affordable rental properties is if you would like to try the BRRR method I would look for properties that are not moving ready or maybe the condition prevents them for qualifying for an FHA loan or low down conventional loan, and do the necessary repairs to make it safe to live in clean and fresh.

One of the properties has about 50K in equity built up with a low interest rate on a 30yr loan. 

I know that the city has been consistently growing without missing a beat in past 30 years, vacancy rate is 3%, rent price was increasing in past 20 years, unemployment is consistently low at 3-5% at past 20 years and so on. 

As low-income owners with a keen entrepreneurial spirit, we balance W2 jobs with side hustles, such as selling custom t-shirts or baked goods.

Someone with a 700 credit score will NOT pay that, but they will get their own financing.I worked at a Pawn Shop some years back.

@Slaven Slugic, get hurricane shutters for the time being in order to receive the wind mitigation credit for insurance purposes.

Would it be advisable to sell one of the investment properties to finance this, or should I explore using a Home Equity Line of Credit (HELOC)?

I like the idea of a lender looking at the deal and not pulling my credit (again), but I'm wondering how paying such a lender back would work, considering a (likely) higher interest rate and short amortization period.