The problem, I'm being told none of the sites are suitable for a inground septic system.

With the ever changing market, I'm looking to learn about how everyone else is finding solutions to the challenges we are facing. 

I looked at the GoFundMe page and watched the video.

If you own the house together, the only options are for one party to buy out the other or sell the house.

Fannie/Freddie both allow up to 90% financing. https://singlefamily.fanniemae.com/media/20786/displayHOWEVER, the  loan level pricing adjustments are HUGE on these loans: So, the rate and costs will be very high. 

Cash from previous BRRRR How did you add value to the deal?

@Nicholas DillonRentometer can give you a rangeZillow also can give a rangeThe best source would be to call a loc a property manager or realtor and have them also give you a range as at end of day they will have most recent and updated numbers and have a better feel for where the market is at

The idea of the property has a lot of potential.

If you start looking all over the US for the perfect investment, you will never take action or you will fall prey to a scammer.

The Long-Distance Real Estate Investing book is a great one to get the lay of the land on doing it from afar, but getting on-site experience will also be important in your journey.