Only Suika listed now - who are 2 other girls? Reimu & Marisa? You know, it's a bit hard to tell, when they're without hair ornaments. :P

The blonde could be Marisa, at least judging from hair lenght and age appareance (The others are either more "lolish" or older, or have longer/shorter hair). The other is almost completely untaggable, unless you count touhou meta-knowledge about Reimu being friend with both Suika and Marisa.
On the other hand, on Pixiv is only tagged as Suika, so maybe both of them are meant to be ordinary people and nothing more.