Citrus Nutritional Spray, a minor element concentrate that you can use as a foliar spray and a soil drench. HD has it. Tangerines often look sickly compared to other citrus.
john

my temple orange and dancy tangerine look the same color as yours, i believe thats healthy as long as the leaves veins are not yellow.
your last picture is a fungus called Mycosphaerella citri, copper will work, but i wouldnt bother if its only minor and cosmetic

leaf miner in your third and fourth picture is typical on tangerines, limes and lemons. some people consider this a cosmetic disease as well but my temple orange was severely overcome by it, i sprayed it with Malathion. theres nothing really organic that will effect it, organic citrus is extremely difficult.

spraying malathion should be a last resort as it will also detract pollinators and wasps which are leaf miners natural predator.

also it looks like you have been visited by the Asian White weevil, they are little white weevils with gray spots, they fall dramatically and glide to the ground looking for leaves to cling to when they are knocked off. neem doesnt effect them, i just knock them down into a jar of water. they are a recent invasive species from Asia.

Here is a link that might be useful: post with my citrus pictures

thanks, Boom and Johnjsr!