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).

I’m thinking of offering an option to buy in the lease maybe after three or five years with no money down and the sale price would be the low end of the Zillow estimate. 

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

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

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.

He will try to justify that joining his program will be your best option, unless you have an unlimited amount of money and time to spend doing the research and learning real estate investing on your own, but the reality is that it does not take much time nor money to learn what he teaches, and even more; it will basically take a dozen of some of the best real estate investing books on Amazon and the time to go through them, subscribing to good sites as this one,  and joining a couple of good REIAs in your area, without having to pay for such expensive and useless mentoring.

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

Is there another option that the kids should consider?