does anyone also feel that Tolstoy knew of the intentionality thesis before he wrote this book?
First of all, I agree that art can try to portray one emotion, but will inevitably represent more since emotions go hand in hand.I think it is impossible to only feel one thing at one time, having "mixed feelings" about something is very common, so therefore it's hard for art to only have one emotion. I also agree with your example of Starry Night. It's a commonly known masterpiece, and seems simple enough, but evokes a flood of emotions when someone actually stops to look at it.
Secondly, I think that Tolstoy was well aware of the Intentionality Thesis, and was trying to amend it like we have been. The artist was creating art, so therfore it is art, but it also has to communicate some sort of emotion in someone to count. Although there are also flaws in that amendment, it is a step in the right direction to becoming more exclusive of a theory.