Some minor changes in recipe: Is it okay to use carrot marmalade instead of orange?
The almonds are pretty much the whole cookie. They get ground up and provide all the bulk and some structure. You could substitute a different kind of nut, though it'll obviously change the flavor and may affect texture too, since different nuts have different hardnesses and different amounts of oil. But leaving them out isn't possible.

The lemon zest is fine, just a different flavor.

And carrot marmalade... again, different flavor, but as long as it's the same sweetness and not any wetter than the orange marmalade it should work. I don't think it'll be as good, personally, though, this recipe is going for a nice strong orange flavor.