The meaning of Japaneese name is explained above. I'll try to explain the name "Kudryashka" since it's in Russian and I am Russian.
"Kudrya" or its diminutive "kudryashka" means "a curl" or "a frizz". Kumako has curly hair so maybe she chose a pen-name connected to this fact.
I don't know why, but Russian words have become popular in anime and manga recently. "Comprehensive Tovarisch" ("tovarisch" = "a friend"), "Sekai Seifuku: Bouryaku no Zvezda" ("zvezda" = "a star")...
And sorry for my poor English.