Yeah, it's very strange that both Wikipedia and GameFAQs use "2-ji" when it is definitely niji and daisen when it is definitely taisen. Though, one may just be referencing the other's odd translation (or maybe it's an official thing, who knows).
I am interested in where Moe Moe Niji Taisen (Ryaku) comes from though (as opposed to Moe Moe Niji Taisen (Ryaku) 2). I see it in the notes section and the represented products field, but
this Wikipedia page doesn't seem to mention anything remotely close to a first game of some sort, without the 2. GameFAQs lists nothing either. Does anyone know which of the games listed on Wikipedia's page this would match up with?