And once construction is done you likely won't find a finance/cash-out option until the business has a couple years of performance under its belt (i.e., business LOC).

House-hacking is one of the best ways to get into real estate, so this could be a viable options.

They offer an option for you to take progress pictures and track your weight as well. 

It's a favorable rate, and given the equity you have in your property, you have a good foundation for securing additional funding without compromising this rate.Considering your property is now an investment, and you're looking into financing options for updates, a VA loan could still be a viable path for you, even in your current situation.

Also, after reading RPI by Brandon Turner, I'm aware of multiple strategies, but since I've never actually invested or bought a property yet, I feel like I'm overwhelemd by all the options, and find it hard to get started. 

You will then have a few options with that rent money....you can put it into principal or you can start saving it to purchase yet another property.

If you have 80k cash, you should have many options to invest using rental financing.

If you do, keep the balance low and take advantage of the zero interest balance transfer option on credit cards.

I inherited a house and am currently exploring options to use it to get money to consolidate some of our debt and potentially have money for a multifamily.

Is there another option that the kids should consider?