I live in a dry climate, not as dry as that, but I'd be wanting to know two things that haven't already been mentioned -
- what does the wind do there? Where I live, we have more rainfall, but a predominant wind that sucks the moisture out of everything. There are solutions to that, so I'm just saying check the prevailing winds as well as the rainfall.
- is the desert there natural or a consequence of farming for a few hundred years? What grew there 500 years ago? Do you have examples of wild land in the area that hasn't been farmed? Or isn't being farmed now?
I think people's 'negative' ideas can be useful, so maybe ask them to reframe them? Someone might know a limitation but not the solution, but you knowing the limitations is very important. Have you put those people off?
I agree that if the Lawton's can green part of Jordan, which is a far harsher landscape then you are considering, then you can permie the land you are looking at. I think how much time, energy and money and skills you have is just as important as all the things about the land and the climate etc. That you have two sets of oldies who've been farming there is a huge asset.