Great finds, shedev. I think the new sandals will go great with your style.
IMO, the UO sandals are pretty close to the Ximenos. It seems to me that the two pairs of sandals would be pretty interchangeable in an outfit, since they are of the same color and aesthetic and have an ankle strap. You would have to ask yourself whether you would end up always reaching for one pair of sandals over the other (splitting wears), or whether you would want to store one pair until the other wears out (stocking up). I personally like the idea of stocking up, but usually by the time the first item wears out, I'm looking for something a little different and am not so happy to have a backup! I guess I like the thrill of the hunt.
I think the Fornarina are a little more different since they lack an ankle strap. They might add a slightly different vibe to outfits than what you already have.