These are certainly writers to read and learn from. They were, to a man, philosophers as well as storytellers, but their philosophy was intrinsic to the stories and (except for Tolstoy) not heavy-handed.
The only point I'd question of the lessons you draw here is on originality. Too many novice writers are so afraid of letting any other writer influence their style that they avoid reading anything. Foolishness! As if your writing would ever be mistaken for some literary giant's! Of course you want to be influenced, influenced by the best. Imitate them all; what you produce will still be your own writing.
I only wish more American students would be exposed to all of these great writers, especially Pushkin.