Board Thread:General Discussion/@comment-26871067-20160608174234/@comment-26871067-20160608183023

In that case I feel like Meruem's page should have it noted in the trivia section that Battle Collection lists him as a specialist at least (same with any other character whose nen type is "unknown" for the series but revealed in a game - I don't know if there are any others).

Seems like a good middle ground - "according to this secondary canon, "[character] is a [nen type]". I know people will argue the canonicity of it, which is why I say trivia section. If it's not contradicted by the primary canon of the manga/anime (images from the opening theme align Leorio with emission, so listing him as "unknown" does count as a contradiction by primary canon), there shouldn't be an issue in doing something like that! Unless it doesn't fit the criteria for trivia of course.