Everything off grid; power, water, self-sufficiency; whether you're doing it or aspiring.
Are you trying to be permitted by the county/local gov?
It's definitely possible to do graywater separate and compost human waste. I've done composting in the past and it can work great. But getting the county (I'm from the US) to sign off on it is really depends on your local government.
One great resource in general is the The Humanure Handbook By Joseph Jenkins
It massively depends on your local code enforcement officer. If they are a dick, don't buy the property. If you haven't met them yet, you will. You didn't say where you are, so ymmv. If you're in Maine, I dug my own, town approved primitive wastewater disposal, and could help.
technically, it can be done (urine capture, composting, humanure, graywater filtering with reed beds) BUT legally it is VERY much a matter of local health and safety ordinances – some areas will allow it with restrictions like the video above, some areas will allow only with special systems in place that guarantee proper sterilization temperatures, and some places will refuse to even consider it …