That just looks like some chaff from the harvesting and packaging process. It's good practice to always rinse beans before use. Lentils (organic or not) are no exception. Place in a bowl, fill with water and drain a couple of times. You should be good to go.
I wouldn’t. At least not when you are talking about true leaves as opposed to cotyledons.
The cotyledons are already part of the embryonic plant and will unfold after the first part of the sprout has reached a certain length. They are perfectly edible in mung beans and contain little or no phytohaemagglutinin (a quick search gave unclear results), which ...
Possibly not. Lectins (the toxins found in raw beans) are inactivated by boiling, but dry heat seems to be less effective (though not entirely ineffective). See https://www.peanutscience.com/doi/pdf/10.3146/i0095-3679-13-1-2 .
Generally you have to soak lentils for many hours, use a pressure cooker to soften them up or a combination of the two. Only masoor dal can be cooked straight away. So I'm guessing you missed a step in whatever recipe you are following.
When cooking any sort of legumes
1) Sort them (if you don't trust it to be pre-sorted)
2) Soak them (make cooking easier, and also more uniform, since they already absorbed moisture)
3) Now you cook them. I don't simmer in the slow cooker, I usually pressure cook them