Wait isn't that Medi's fairy? It has little wings. I don't believe it's hourai. Don't remember what the little fairy has been nicknamed right now though.
Itdefinitely looks like Su-san to me because of the style of the top and skirt, not to mention the wings. As far as confirming it, though... I think I might know a nico douga video that this is from - I'll check and see.
It's Hourai alright, which does indeed make much more sense. The artist made a version that originally just had Shanghai (that is, the blue one) and Marisa. They later uploaded a version with all three of them.
She looks less like Su-san with the clarity of the video version, but the way this artist draws still does remind me of her quite a bit. (On that note and with Kabi's comment in mind, almost all of the commenters on the video call her Shanghai when first she shows up in the video for some reason and at least one calls her Su-san later on....so it appears we aren't the only ones puzzled.)
First of all, this is too cute. I want to hug those dolls... Maybe Marisa, if she promises not to Master Spark my face off.
Second, this IS Su-San. Go to Touhou Wiki and you should see, she dresses just as Medicine (Red and Black) and has wings (even though Alice's dolls USED to have wings before.) Also, in every description, the ONLY thing differencing Hourai from Shanghai is that fans themselves place a bonnet on Hourai. Other than that, Shanghai and Hourai look the same.
After looking around a bit, she certainly matches perfectly to Su-san, but matter of opinion I suppose. Really depends on if the person that made this went by official (the shanghai and hourai dolls have the same sprite) or fanbase (never seems to stick with a constant coloring style for shanghai)...