What begins with e, ends with e and has one letter? Now change two letters and you get me I have horns

I'm green and crunchy, usually eaten raw. My little brothers are often pickled.

Victoria, Albert, Van, and Tana are all examples of me What am I?

The alphabet goes from A-Z, but I go from Z-A. What am I?

I drift like cotton through the blue, changing shape as dreamers do. I appear soft to the sight but not to hold, I paint the sky in gray or gold.