Again I don't think this is a 2024 or even early 2025 type problem, I am more so looking to maintain my current returns, while having the ability to scale further in the 3-5y horizon while tapping into equity built over the previous few years of renovations and property stabilization.Yes a normalized market is a great opportunity to grow the portfolio, which I certainly plan on doing, I just want to ensure I can tap into the dry gunpowder that has taken a lot of effort to create the past two years.

The limited amount of built as multi family is scare, and even less common do they come out to the market. 

Is this even a good deal or should I keep looking for more cashout refi options? 

I’ve heard about ‘gap funding’ for fix & flips to cover down/closing/holding costs in addition to the hard money loan for most of the purchase price & rehab, but how realistic is it to secure that type of funding?

If they're in D class neighborhoods (or even lower C class as well), then your options are pretty limited.

Before you even start spend a few hours and a lot of discussion to sort out every possible contingency.  

do You need money asap?

And even if we do there's still a lot of work to do on those insurance premiums. 

To finance the deal, I'm thinking of using hard money and heloc from 1 of my properties.

That is definitely your best bet... they will help you connect with a property manager, attorney, and contractor if needed.