I can answer on a couple of points only. You don't say what breed your polled ewes are. Texels, which are polled, often have lumps, bumps and even scurry horns, and I have seen them on Shetlands too. If they are where horns would be, then yes they are a throwback to hornedness. The only drawback I can think of is that if they get knocked and they bleed, then they could attract flies, so put a drop of Crovect or whatever you use on them when you do the sheep.
Sheep love nettles especially in winter and will also eat young dock leaves. They are full of vitamins and micronutrients so are great for sheep to eat, the docks in a lesser quantity than nettles. The sheep will regulate how much they need.
Docks which have gone to seed are not a good idea to leave around - the seeds and dried stems will stick in the sheep's fleece, decreasing the value of the fleece, whether for skins or to sell to the BWMB, and annoying the sheep, being spiky. The seeds will also contribute to the seed store in the ground - dock seeds are still viable after 20 years, so clearing them is a longterm project.