^ That is actually a really good catch- it could be a case of samefacing, and twintails are a pretty common hairstyle for the eternally 12 year old persona idols get paid to project, but having the yandere be a fellow idol would eliminate a ton of logistical difficulties when it comes to stalking. It also contrasts her to the protagonist, since she's actually successful and employed and knows about Cirno's 'real' persona as opposed to her idol persona as a result of working together with her, making her love more 'genuine' than the MC's in a twisted sort of way.
Besides, if our protagonist actually ends up with the yandere, then the title will still hold true- just in a different way than we'd initially expect.