I can't see the picture, so I'd offer that caveat to the rest of my post.

Touring and cyclocross bikes can take some fairly beefy tires, but it would pay to look at the exact specifications of any given bike to determine the max tire width that the bike can accommodate. My Jamis touring bike's tires are wider than my road bikes and I could put even wider tires on the bike if I wanted to. Presumably, your local shops have an understanding of what type of tires are needed to get through the sand. Have you asked them about it?

As for women specific bikes versus unisex/men's. That depends entirely on your body and proportions. Some women need WSD geometry; some don't. Test ride all that you can to get a sense of what works for your body. Apart from geometry, women specific bikes often come with narrower handlebars and short reach shifters/brakes, so if you end up with a unisex frame, you may have to tweak a few things to make it truly fit, but those fixes don't have to be overly expensive.