I'm not familiar with what will or won't thrive in Ella's region, but I am aware of which veggies, able to grow in my area, are considered good sources of calcium.
Fresh soybean (edamame)
Nopales (prickly pear cactus pads)
Almonds and stinging nettle are also decent sources for calcium, though they don't grow in my area. I think both will grow for Ella.
Truthfully, I don't think about which veggies to grow according to nutriental content. Perhaps I should. But I believe that if I'm eating a wide variety of fresh foods and stay away from most commercial foods, I'll be doing fine with the nutrition. Once upon a time I used to micro-analyze stuff. It was an aspect of my job. But I've drifted away from that.
Wide variety makes sense to me. I tend to grow a little bit of lots of different things. I have dozens and dozens of micro garden beds, so often whatever is ready to pick becomes dinner, with nothing leftover. This habit causes my neighbor to shake his head. He wants me to grow large beds of one item, more like a traditional farmer. Then sell or store the excess. While I may only plant a small part of a seed packet at a time, he will invariably plant the entire packet no matter how large. ..... Different strokes for different folks.
By the way, my homestead also produces dairy (via trading), meat, and eggs. Sources of calcium. And I could always trade for small fish, pressure cook them, and eat bones 'n all. Calcium isn't difficult for me to find. And heck, there's always coral sand......a bit gritty but edible.