Hm, I got "yew-tree" for Ewen and "lord of the woods" for Keith - I hadn't picked up the other two meanings. I was happy enough with an arboreal connection for the two of them (possibly significant in a later chapter..?) but those meanings you've found are also quite fascinating and satisfying!

But. She was working at Oxford at the same time as Tolkien. I daresay some of that linguistic stuff osmosed across!